ASBOG

Briefly define the following tools used in field investigations: auger, casing, cone penetrometer, shelby tune, split-spoon sampler

- An auger is a drill attachment used to sample loose surficial material -Casing is a metal pipe placed into a borehole to prevent solid or liquid material from intruding into the hole -The cone penetrometer consists of a cone, typically angled from 30 to 60 degrees, used to determine the force required to thrust downward into silty or fine to medium coarse unconsolidated materials for the purpose of obtaining information that a foundation or soils engineer may use to calculae load bearing values -A shelby tube is a thin walled soil sampling tube, 12 to 30 inches long, attached to a special rod adapter or sub by means of machine screws. The device is designed to take soil samples by pressing or pushing the tube down into the formation sampled -A split spoon sampler is a type of barrel sampler that is used to collect disturbed soil samples

Define the following terms often used in geophysical field investigations: invaded zone, API units, rippability, test pits

- The invaded zone is the area affected by the drilling of a borehole in which physical parameters have been altered. The invaded zone lies in between the flushed zone and the un-invaded zone. - When radioactive well logging, gamma rays are measures according to an American Petroleum Institute (API) unit standard -Rippability is a measure of the relative ease or difficulty with which an earth material can be dislodged and removed by machine-drawn rippers or rigid steel tines. Rippability refers to the ease with which a material can be excavated mechanically - Test pits are mechanically excavated surface cuts used to investigate shallow sub-surface conditions. Test pits are used to sample geologic materials in areas of restrictive overburden or vegetative cover. Test pits are also excavated to investigate young faults

Summarize the following field methods: gravity survey, ground penetrating radar, percolation test, rotary drilling, seismic reflection, seismic refraction, standard penetration test.

-A gravity survey is a collection of measurements made over a region with a gravimeter to determine differences in the earth's gravitational field -Ground penetrating radar is used for mapping of subsurface materials by sending a radar impulse below the surface -A percolation test is used to determine the rate, expressed as either velocity or volume, at which water percolates through a porous medium -Rotary drilling is the typical way of drilling a deep well, and is accomplished with a drill bit that has been cooled and lubricated with drilling fluid -Seismic reflection is a technique to determine the structure of subsurface formations by making use of the times required for a seismic wave to return to the surface after reflection form underlying formations -Seismic refraction involves seismic waves that can travel large horizontal distances along distinct interfaces in the earth -A standard penetration test analyzes the conditions of geologic materials by counting the number of times a hammer must be dropped in order to drive the sample rod 18 inches into the soil

Define the following terms relating to water wells: area of influence, cone of depression, drawdown, and well efficiency

-The area of influence of a water well is the area surrounding the well within which the piezometric surface has been lowered when pumping has achieved the maximum steady rate flow - The piezometric surface is an imaginary surface representing the total head of ground water defined by the level to which water will rise in a well - The cone of depression is a conical area that is produced in a water table or in the piezometric surface by pumping. It forms because water must flow through progressively smaller cross sections as it nears a well, steepening the hydraulic gradient - Drawdown is a change in the hydraulic head at a well due to pumping relative to background conditions - Well efficiency refers to yield and recharge characteristics of a well

Explain what Brownfield sites are, and the steps involved in a Brownfields site redevelopment

A Brownfield site, or Brownfield, is an abandoned, idle, or under-utilized industrial or commercial site that is a challenge to city planners due to complications caused by pollution. Brownfield sites have the potential to be reused once they are cleaned up. Land that is more severely contaminated and has high enough concentrations to qualify as a Superfund area would not classify as a Brownfield site. Many contaminated Brownfield sites sit idle and unused for decades because the cost of cleaning them to safe standards is more than the land would be worth after redevelopment. The requirements for becoming a Brownfields site are summarized in a Brownfields Revitalization and Environmental Restoration Act of 2001. There are three phases of Brownfields redevelopment. In phase 1, the degree to which the site has been contaminated, and the possible financial or legal consequences of development are examined. In phase 2, more comprehensive investigations are performed severe cases. In phase 3, the site is cleaned up.

Describe what a bailer test is and what it is used for.

A bailer test is one of 3 available single well hydraulic tests that yield estimates of the hydraulic conductivity of aquifer materials around a single well. These single well tests are less accurate than multiple well pumping tests but are an efficient option for obtaining an inexpensive estimate of relative hydraulic conductivity. The bailer test, also referred to as a slug test or falling head test, involves the rapid addition or subtraction of a known volume of water from a monitoring well. The predetermined volume of water from that is added or removed is referred to as a slug. Observations and measurements of the well characteristics are then collected with careful documentation of required recovery times. The essential requirement is that the slug be added or removed as quickly as possible. Well water level or pressure is then monitored. This test is also used to determine transmissivity and storativity.

Explain how to interpret map scale

A bar scale is typically a graduated line placed near the bottom center of a map that displays distances on the actual map. Bar scales usually show miles and kilometers and allow the map user to directly measure distances on the map by observing the number of defined graduations (miles, kilometers, feet) between desired points on the map. A ratio scale is somewhat more difficult to use than a bar scale. The ratio used for map scales is always in the form of 1:X. In a ratio scale the numerals do not refer to any specific unit or length of measure. Accordingly, the map scale of 1:5,000 can be interpreted as "one unit on the map is equal to 5,000 units on the ground" or "one inch on the map equals 5,000 inches on the ground". Some commonly used map scales have convenient conversion factors such as 1:50,000 is equivalent to 2 centimeters equals one kilometer, and 1:24,000 is equivalent to 1 inch equals 2000 feet. Maps may be prepared at any scale depending upon level of detail required.

Boring logs must be as detailed as possible to provide the best records available. List the minimum contents of any boring log.

A boring log, or drill log, is the record of the events and the type and characteristics of the formations penetrated in drilling a core hole. A detailed boring log must contain the following information: - drilling company and names of drillers - type of drill rig used - job location and location sketch - date, name, and number - boring number - ground surface elevation at location of hole - type of sampler used - hammer weight and fall -pressures required - condition of samples - water levels at beginning and completion - completion status - backfill materials and methods - monitoring equipment - perforation intervals and grout intervals - full summary of the soil and rocks found at the site. The boring log must also contain any specific information pertinent to the day' drilling and/or notations for the following drill shift.

Describe in detail how a caliper log works, and mention the reasons why borehole diameter might change

A caliper log is a well log that shows the variations with depth in the diameter of an uncased borehole. It is produced by spring- activated arms pressing against the sides of the well bore that measure the varying widths of the hole as the device is drawn upward. The caliper consists of a central core with a potentiometer surrounded by at least three arms. The diameter data for the borehole are recorded by the potentiometer. An acoustic caliper, on the other hand, records the varying diameter of the borehole by means of three ultra sonic transmitters. It is important to test for changes in borehole diameter, since these are common when different drilling methods are used, or when the surrounding rock has fractures, water, or caving. Borehole diameters change according to lithology and groundwater activity.

Describe the following types of logs used to describe a borehole: caliper logs, gamma ray logs, neutron logs, and well logs.

A caliper log produces a physical profile of the diameter of an un-cased borehole with the use of moveable calipers that record variation in the borehole wall. A gamma ray log is used to assess the type and amount of gamma radiation produced by the rocks in a particular borehole. A neutron log assesses the radioactivity log curve in the borehole by neutron emanation. A neutron log is used to estimate the density and porosity of a rock formation. A well log is a graphic representation that displays a specific characteristic of the rock in the well versus the depth of the well. A well log is a record of the measured physical or chemical characteristics of the rocks encountered in a borehole. Measurements are made by a sonde as it is withdrawn from the borehole by a wire line. Several measurements are usually made simultaneously with the resulting curves being displayed side by side on a common depth scale.

Discuss the types of information that a rock boring lon should contain to accompany the rock core extracted.

A complete rock boring log must contain the following information on the heading: date, location, loggers name, personnel, drill pressure, drilling rate, drilling fluid and bits used, and any other pertinent notes. The actual core logging consists of describing and charting: drill depth, lithologies, facies changes, any veining and faulting encoutnered, core recovery percentage (missing core), rock/color, rock hardness, specific mineralogy, and some general texture/structural characteristics. The textural and structural features that need to be mentioned include the following: formation, lithology, grain size, bedding and foliation, lineation, and fractures. Core samples are then digitally photographed and entered into a computer for detailed analyses and retained so that there can be a record in the event that the rock sample is damaged or misplaced.

Describe how a cone penetrometer works, and discuss what types of information it provides.

A cone penetrometer is used to assess the resistance of the soil to penetration by a standardized rod at a constant pressure. This technique can work on all but very dense soils. The penetrometer operates by being pushed through a soil at a constant rate of force. A sensor records the amount of force and time that was required to reach certain distances within the soil. These data obtained through the used of a cone penetrometer can provide information about undrained shear strength, subsurface structure, and soil density. Cone penetrometers consist of a rod with a conical point that is typically angled from 30 to 60 degreed. The diameter of a cone penetrometer is approximately the same size as an A-size diamond drill rod.

Discuss how the constant rate pumping test differs from the bailer test

A constant rate pumping test stimulates an aquifer or well through pumping and by observing the aquifer's response in observation wells. The constant rate pumping test is performed in order to measure the hydraulic conductivity, storativity, or specific yield of an aquifer or well. The constant rate pump test is a multi well test. A bailer test is one of 3 available single well hydrualic tests that yield order of magnitude estimates of the hydraulic conductivity of aquifer materials around a single well. These single well tests are less accurate than multiple well pumping tests but are an efficient option for obtaining an inexpensive estimate of relative hydraulic conductivity. The bailer test does not require pumping. The bailer test is used if the transmissivity of the material the well is completed in is too low to realistically perform a proper pumping test.

Outline the information that should be included in a detailed soil description.

A detailed soil description methodology is outlined in the Unified Soil Classification System (USCS). This classification system divides soils into three major subclasses based on general grain size and also contains provisions for other descriptive attributes of soils. The USCS description is foten the initial field description of a soil. Engineering, or geotechnical, soil descriptions are more detailed but include the full USCS attributes. Geotechnical soil descriptions include many other propertires of the soil such as moisture content, penetration (density) and shear strength test data, as well as other descriptive elements. This facilitates transition of direct field observation into soil behavior prediction and design engineering of foundations and strucutres. The color of the soil must be described in relation to a standardized reference for color.

Describe the anatomy of fault sides

A fault is a fracture or a fracture zone in crustal rocks along which there has been displacement of the two sides relative to one another parallel to the fracture. The displacement may be a few inches or many miles long. The dip of a fault (the angle of the fault relative to the horizontal) can be between 90 degrees (vertical) and 0 degrees (flat-lying). The opposing sides of a fault are referred to by the terms footwall and hanging wall; The lower surface is the footwall and the higher surface is the hanging wall. In vertical faults there is no distinguishable footwall or hanging wall since both surfaces are vertical.

Outline the steps taken to operate a fixed-piston sampler, and discuss in which types of soils it can be used.

A fixed-piston sampler forces a short tube-like device into soils, soft rock, or rock material without utilizing sample tube rotation. The tube is driven into the material to be sampled either hydrualically or is pounded in with a drive hammer. A second tube is then forced inside the first tube and is rotated to separate it from the soil column below. Fixed piston samplers are best for obtaining samples of soft, wet soil, or any soil below the water table. A sample in an undisturbed state is generally obtained with the fixed-piston sampler. A fixed-piston sampler is also referred to as a drive sampler. These samplers are typiclaly equipped with a free or a retractable-type piston that recoils up inside the barrel of the sampler while remaining in contact with the top of the soil.

Discuss how flow nets can be used to help design a dam

A flow net is a graphical representation of two dimensional steady state groundwater flow through aquifer. Construction of a flownet is often used for solving groundwater flow problems where the geomoetry makes analytical solutions impractical. These diagrams are often used in the design of dams, to determine where water pressure will tend to accumulate. On such a diagram, the maximum equipotential line will be the horizontal line at the base, while the minimum equipotential line will be the horizontal line at the base of the downstream area. Flow lines will then be drawn to show the possible paths of water beneath the structure. The shortest flow line will be the curve that joins the intersection of the dam and the upstream ground with the intersection of the dam and the downstream ground; the line drawn along the impervious boundary beneath the ground at the base of the dam will be the longest flow line

Describe what a flownet is, and how it can be used

A flownet is a graphical representation of two dimensional steady state groundwater flow through aquifers. A flownet is often used for solving groundwater flow problems where the geometry makes analytical solutions impractical. The method is used as a first check for problems of flow under structures such as dam or retaining walls. The method consists of the construction of a graphical flow area with stream and equipotential lines, which are everywhere perpendicular to each other, making a curvilinear grid. Mathematically, the process of constructing a flownet consists of contouring the two harmonic or analytical functions of potential and stream function. These functions both satisfy the Laplace Equation and the contours represent lines of constant head (equipotentials) and lines tangent to flowpaths (streamlines). The construction of a flownet only provides an approximate solution to the flow problem, but it can be quite good even for problems with complex geometries.

Discuss the defining characteristics of rock fractures

A fracture is defined as any break or failure in a rock, whether or not it causes displacement, due to mechanical failure by stress. Fractures include cracks, joints, and fracture cleavage. The defining characteristics of fractures are orientation, width, extent, density, and displacement. These characteristics define the stress history of the host rock, both locally and regionally. Both qualitative and quantitative analyses of fracturing and regional fracture patterns can lead to determinations of localized and regional tectonic events and aid in the reconstruction of complex multi-stage deformational histories of an outcrop or area. Cleavage occurring in deformed but only slightly metamorphosed rocks is called fracture cleavage. It consits of groups or sets of closely spaced parallel joints and fractures

Review the general three-dimensional characteristics of lithologic features that may be found on a map.

A geologic map displays geology occurring on the surface but also provides a three-dimensional picture of the quadrangle. This is accomplished through the use of structural symbols and cross sections. In a general sense, sedimentary rocks often have a consistent thickness throughout a quadrangle. However, this is by no means universally true. Many times in cross sections and in structural analyses, thicknesses of sedimentary units are generalized. Igneous bodies will be described by outcrop patterns and sub-surface structure and dimensions. In many instances, outcrop pattern of igneous rocks will not represent total size or extent of such rocks and referring to cross sections becomes essential. The geologic map is a 2-dimensional depiction of surface geology with the 3-dimensional attributes of lithologic units represented by symbology.

Describe the elements of a landslide investigation, and tell what it is used for

A geologist will perform a landslide investigation in order to determine whether a landslide is likely to occur in some location where a structure is to be placed. A landslide investigation has a number of steps. The first step in performing such an investigation is to assemble historical information on the natural and human history of the region. The following sources are useful for acquiring this information: municipal files, notes from other geological projects, aerial photos, reports, and maps. A full investigation of the subsurface conditions, including topography, drainage, geological structure and weathering, and faults, should be performed before any construction is initiated. In general, all the data should be aimed at locating any weak regions in the location.

Explain how gravity surveys are conducted, and describe the information they provide.

A gravity survey may be conducted as an airborne data collection or as a land-based study. Gravity surveying is a geophysical method that measures irregularities or anomalies in gravity attraction produced by differences in the densities of rock formations. Anomalies are identified based on differences between the observed value of gravity at a point and the theoretically calculated value for that point. Theoretical values are calculated based on a gravity model that assumes a generalized hypothesis of variation in subsurface density as it related to surface topography. Results are interpreted in terms of lithology and structure. Gravity surveys have application in many earth science-based industries including mineral exploration, oil and gas exploration, engineering geology, and civil engineering. Gravity surveying is also a used in geologic research.

Define the following less commonly found fault types: detachment, growth, listric, oblique-slip, thrust

A growth fault is similar to a normal fault, except that it occurs simultaneously with the deposition of sedimentary rock. This kind of fault is typical in areas characterized by on-going sedimentation such as in river deltas or any other region in which the sediments are subsiding at a fast pace. Detachment faults are low angle regional normal faults typically with displacement in the tens of kilometer range. These large faults are found in areas of extensional tectonism and usually juxtapose unmetamorphosed footwall rocks. A listric fault has a curved shape with the angle of the curve greatest near the surface. An oblique-slip fault is one with both strike slip and dip slip components. The footwall and hanging wall do not move exclusively along the fault's strike or dip, but instead move in a diagonal direction. A thrust fault is essentially a low angle reverse fault in which the plane of the fault is between zero and 45 degrees.

Describe how physical or chemical characteristics are used to identify minerals.

A mineral is defined as "a solid inorganic substance of natural occurrence." Minerals can be identified by means of their physical or chemical characteristics. The physical characteristics of a mineral are a direct result of the chemical composition of that mineral. Physical characteristics that can be used to identify a mineral are: crystal habit and symmetry, cleavage, fracture, crystal twinning, specific gravity, color and streak, luster, luminescence, radioactivity, and magnetism. The possible combination of all chemical elements on Earth represents millions of compounds. Despite this fact, only some 2400 minerals have been described to date. All minerals possess a unique internal structure, and most have unique chemical compositions. Minerals are thus highly identifiable by chemical analyses. In chemical analysis of a mineral a determination is made of the relative amounts of elements and their oxidation states. While minerals can normally be identified by physical characteristics, they can also be identified by the color of the flame they produce when burned, a function of chemical composition.

Discuss the possible inputs of groundwater that could be included in a model of ground water inventory

A model of groundwater inventory can contain multiple different inputs of groundwater: - the underflow beneath the bed of streams in the area is one way the groundwater can be introduced to an aquifer - an aquifer may receive water from irrigation or from a recharge well - precipitation or other runoff can end up in an aquifer through percolation or as infiltration - groundwater inputs can come from the water that flows into a stream or river when this recharge reaches the water table - the confining bed around a perched aquifer or barrier between two aquifers may become altered, causing groundwater inflow - groundwater inputs could also come from glacial and bedrock sources, depending upon yields and drawdown and transmissivity characteristics

Explain what sorts of materials or structures neutron logs can be used to measure.

A neutron log is a strip recording of the secondary radioactivity arising from the bombardment of the rocks around a borehole by neutrons from a source being caused to move through the borehole. Because hydrogen is such an effective moderator of neutrons, neutron logs are often used to gauge the porosity of subsurface rock. Because resistivity is related to porosity, neutron logs can also give a good reading of this characteristic. A neutron log is also able to provide information about the borehole diameter, ground water pressure, and the salinity of groundwater. It should be noted that neutron logs are notorious for providing odd results when used to measure the porosity of gypsum, coal, gas-bearing formations of clay, and shale.

Describe the theory behind neutron logging and discuss what neutron logs are used for.

A neutron log records secondary radioactivity arising from the bombardment of the rocks around a borehole by neutrons emitted from a source as the tool is raised upward through the borehole. Neutron logs are used in conjuction with other types of logs for the identification of the fluid-bearing zones of rocks. This test also utilizes a neutron source being withdrawn throughout the length of the borehole. A measurement is taken of the energy lost by the neutrons after they come into contact with the subsurface materials. Because this change in energy is largely due to the quantity of water underground, a neutron log is also effective at measuring the porosity of the subsurface materials. Neutrons that enter rock formations induce additional gamma radiation, which is measured by use of an ionization chamber. The gamma radiation so induced is related to the hydrogen content of the rock.

Explain what conditions are necessary for a petroleum pool to exist

A petroleum pool is a field or deposit with similar pressure and reservoir characteristics. A petroleum pool that has a common petroleum/water contact and a distinctive pressure regime is a fundamental unit of petroleum accumulation, and can be treated as a natural object. A petroleum pool is a naturally occurring and quantifiable accumulation of oil. The conditions necessary for the formation of a petroleum pool are: source of hydrocarbon, permeability and porosity of availble host rocks, stratigraphic or structural traps available, and a transportation path from source to reservoir. Structural traps are formed by a deformation in the rock layer that contains the hydrocarbons. Fault related features also act as structural traps. Stratigraphic traps are formed when impermeable barriers or beds seal a reservoir bed or when permeability changes (facies change) within the reservoir bed itself.

Describe what a pump-in test and a slug test determine, and how they are conducted

A pump-in test, also known as a constant head test, involves a measured discharge of water into a monitoring well to maintain a constant water level within the well. The mehtod is more commonly used where the aquifer materials have moderate to high hydraulic conductivity. The pump in test is a single well hydraulic test used to obtain order of magnitude values of hydraulic conductivity. It is used to determine the measure of the horizontal hydraulic conductivity of an aquifer. A slug test is a particular type of single well test in which a known amount of water is quickly added or removed from a groundwater well and the change in hydraulic head is monitored through time. A slug test does not require pumping. The slug test determines the near well aquifer characteristics of the material the well is completed in. Slug test can determine transmissivity and storage coefficient.

Compare and contrast sag ponds and aligned springs, both of which are groundwater related features found along faults

A sag pond is a small body of water that occupies a depression along the trace of an active fault. Uneven settling along the trace of the fault allows a small pond to collect through upwelling of groundwater along the fault. Surface runoff may contribute in part to sag pond formation. Sag ponds are most often found along active strike slip fault zones. Aligned springs are occurrences of water at the surface along a fault trace related to normal and artesian groundwater occurring along the fault. When the fault shifts, groundwater that had previously been traveling through porous rock may be diverted up to the surface. Aligned springs are an effective ground indicator of faults that may be hidden or unknown.

Review the categories and characteristics of seismic waves, and discuss their propagation

A seismic wave is a wave that travels through the Earth, most often as the result of an earthquake. Seismic waves are also caused to propagate by the continual pounding of ocean waves against cliffs, or by the wind. The two types of seismic waves are body waves and surface waves. Body waves travel through the interior of the Earth along pathways that are bent by the varying density and stiffness of earth materials encountered. Two individual types of body waves are: P waves, also called longitudinal or compressional waves; and S waves, referred to as transverse or shear waves. P wave propagation involves the ground being alternately compressed and dilated in the direction of propagation. S waves propagate as the ground is displaced perpendicularly to the direction of propagation. Surface waves are analogous to the waves that form in water and travel just under the Earth's surface. They travel more slowly than body waves. Because of their low frequency, long duration, and large amplitude, they can be the most destructive type of seismic wave.

State what information gamma ray logs provide, and discuss how different rock types would vary on a gamma ray log.

A spectral gamma ray log is the record of the radiation spectrum and relative intensities of gamma rays emitted by strata penetrated in drilling. Various elements can be differentiated due to the different energies contributed by each type of gamma radiation to the sun total natural gamma ray signature. A standard gamma ray log provides the log curve of the total intensity of natural gamma radiation emitted from the rocks in a cased or uncased borehole. It is used for correlation, and for distinguishing shales, which are usually richer in naturally radioactive elements, from sandstones, carbonated, and evaporates. Amount of gamma radiation induced is also a measure of hydrogen content. Clays and shales tend to have more concentrations of radioactive elements than other types of rock. Volcanis ash increases gamma radiation. The most radioactive rocks are shale, arkose, and granite.

Discuss how spontaneous potential (SP) is logged and what is represents.

A spontaneous potential log is the record of the naturally occurring potential differences between formations that are found in the borehole. These potentials will tend to develop between the formation water, the surrounding rock materials, and the borehole fluid. Spontaneous potential is measured in DC voltage, and is typically accompanied by a measure of electrical resistivity. Two factors that can affect SP are temperature and quantity of clay. The vertical line drawn through the greatest positive value of spontaneous potential measured is known as the shale line or the baseline, while the vertical line drawn through the most negative value of spontaneous potential measured is known as the sand line. Spontaneous potential logs can determine the thickness of a bed, as well as the amount of salt in the formation water.

Distinguish between a stratiform and a stratabound deposit

A stratiform deposit is one in which the target rock or mineral is contained in or constitutes layers in a sedimentary, metamorphic or igneous layered sequence. Stratiform deposits are strictly syngenetic deposits, meaning the mineralization formed at the time of the deposition or crystallization of the host layer. This deposit will not necessarily be confined to a single bed or strata but will assume the general tabular shape and aspect of deposits hosted by a particular bed. Strataboung deposits are mineral deposit contained in a single stratigraphic unit. Stratabound deposit refers to a number of differently oriented orebodies contained typically within a sedimentary rock unit. Stratabound mineral deposits are usually epigenetic deposits such as metasomatic replacements. A stratabound deposit is generally controlled structually and chemically by the strata or horizon which hosts it.

Discuss the uses of test pits in borehole geophysics

A test pit in borehole geophysics is generally used to calibrate instruments before insertion into a drillhole to account for local conditions. For example, before a downhole gamma ray survey, careful calibration of the spectral gamma probe in a test pit of known isotope concentrations permits the process of spectral stripping to be done. Spectral stripping identifies the individual elements contributing to the total gamma count through the comparison of the total spectrum against known standards for individual elements. Test pits are also used to make a preliminary study of the ocnditions below the surface prior to drilling. The presence of surficial units that may impede drilling are noted. The test pit is an essential prerequisite before committing expensive and delicate instrumentation.

Outline the steps taken to operate a thin-walled push-tube sampler, and discuss in which types of soils it can be used.

A thin-walled push tube sampler is best for evaluating a soil that is cohesive and even-grained. Congolmeratic, rocky or extremely non-cohesive soft soils should not be sampled using a thin-walled push tube sampler. One common example of this kind of sampler is the Shelby tube. The sampler typically has a three or 5 inch outer diameter, is 12 to 30 inches long, and has a wall thickness of approximately 11 or 14 gauge. The thin-walled push tube sampler is perated by inserting the tube completely into the material to be sampled and twisting to separate the soil sample from its surroundings. The tube is then carefully removed from the ground, and the sample is removed from the tube hydraulically.

Review the principles used when siting tunnels, including things that should be avoided, and how the area should be characterized

A tunnel should be oriented such that it cuts across geology and intercepts desired zones of interest. Rock competence and ground stability at the portal site and available space for tailings are of concern. In general, areas with high groundwater and weak subsurface formations should not be tunnel sites. If at all possible, a tunnel should not cross a large fault or void in the subsurface unless it is a targeted zone such as a vein or ore body. Pre-tunneling core drilling data will assist in layout of access to underground target, environmental concerns, and storage and site plan issues. A major concern in tunnel siting is avalanche danger. Tunnels must be sites out of direct and recurrent avalanche zones.

Describe, with specific details, the emission of neutrons from a neutron log probe, subsequent interactions of neutrons and surrounding material, neutron capture, and detection

A typical neutron log probe emits neutrons from a source utilizing a mixture of beryllium and americium. Freshly emitted neutrons lose energy as they come into contact with geologic materials and fluids encountered in the borehole. This process is known as moderation. When neutrons are first emitted they typically possess neutron energy level greater than 10^5 electron volts. After contact with moderators in the borehole, they become epithermal neutrons with an energy level between .1 and 100 electron votls. When a neutron sinks below .025 electron volts, it becomes a thermal neutron. The element that most effectively moderates neutrons is hydrogen and hence, water. Neutron logs are effective in assessing the level of water in the subsurface materials.

Explain the concept of the fold line, and discuss how it can help solve graphic constructions.

A useful visual tool in geologic map interpretation involves the use of a fold line. A fold line can be laid out along the direction of the dip of a bed or geologic horizon when strike, dip, and the direction are indicated on the map. One half of the map will then indicate the horizontal map view, while the other half will indicate a cross sectional, vertical view. The vertical view will contain the dip line, while the map view will include strike line and dip direction. This method of orienting a map can help you to envision the actual geometric relationship between orientation of dip, dip direction, and strike. This graphical method is useful in envisioning underground structure or for plotting underground intersections between tabular geolgoic features or drill hole intercept.

Describe what a water quality test quantifies, and how data is presented

A water quality test quantifies nine parameters leading to a water quality index. The parameters quanitfied in a water quality test are: temperature, pH, dissolved oxygen, turbidity, fecal colliform bacteria, biochemical oxygen, total phosphates, nitrates, and total suspended solids (TSS). The National Sanitation Foundation (NSF) surveyed 142 people representing a wide range of positions at the local, state, and national laevel about 35 water quality tests parameters available for possible inclusion in this index. The above mentioned nine factors were chosen and some were judged more important than others, so a weighted mean is used to combine the values. The information obtained from a water quality test may be presented in a table or a graph. The graphs that are used to display this kind of information include bar graphs, pie charts, trilinear charts, and Stiff diagrams.

Describe what information is shown in a well log, and discuss what information it provides.

A well log records measurement of the characteristics of the rock and structure encountered in a borehole. The log is graphically plotted, usually as a continuous function of depth. Measurements are collected with a sonde that is withdrawn from the well by a wire line. Several measurements are usually made simultaneously. Measurements include: resistivity studies conduted during electrical logging, acoustic or caliper logging data, gamma ray logging data, neutron logging data, and spontaneous potential logging data. The most common types of well logs are resistivity logs and radioactivity logs. Other well log types commonly produced are specific curve types including sonic logs and gamma ray logs. A well log can provide information about porosity and permeability, geologic structure (if multiple logs are used), and stratigraphy.

Distinguish between the following terms related to dissolved materials in groundwater: absorption, adsorption, sorption, ion exchange

Absorption is the assimilation, the taking up, the incorporation of one substance into another. An example is the absorption of a liquid into a solid or the absorption of a gas into a liquid. Adsorption is the adherence of gas molecules to the surface of solids with which they are in contact. The assimilation of gas, vapor, or dissolved matter on the surface of a solid or liquid is also defined as adsorption. Adsorption can also occur as an attachment of a thin film of liquid or gas, commonly of monomolecular thickness, to a solid substrate. The term sorption refers to any type of retention of a material on the surface of another material when the mechanism is unknown or not specified. Ion exchange refers to the migration of ion across a boundary such as the fluid-solid boundary. Ion exchange is typically reversible but can be non-reversible

Describe what a statistical analysis of well monitoring data would entail, and what assessment monitoring requires, as outlined by TEGD guidelines

According to the TEGD, after a number of years of operation of a monitoring well program, it should be possible to determine mean and variance for each monitoring well in the system. Data from down gradient and up gradient wells should be comapred annually to that of background wells. The TEGD stipulates that if an exceptional amount of variation occurs, it should be investigated and rectified. If the well sampling program is large, it can be analyzed using Cochran's Approximation to the Behrens-Fisher (CABF) t-test. Cochran's approximation is based on Cochran's theorem, a statistical method of analyzing variance. If the well sampling program is small, it can be analyzed using the Averaged Replicate (AR) t-test.

Describe in detail the structure of a monitoring well that is built to follow TEGD guidelines

According to the TEGD, monitoring wells must adhere to the following specifications: the borehole must be between 10 and 12 inches in diameter with the well completed in the rocks below the aquifer. A well casing made of Teflon or stainless steel should be screened in the saturated zone, with 2 feet or less of filter pack above the screen. This filter pack should be made out of clean quartz sand or glass beads. The well casing should be made out to cement in bentonite below the frost line, with the concrete cap and well apron above the frost line. This apron should be at least 4 inches thick and 6 feet in diameter, with a surveyor's pin embedded.

Discuss how a monitoring well site would be constructed in order to follow TEGD guidelines.

According to the TEGD, the best management practice for the drilling of a monitoring well is with drilling techniques and tools that cause the least disruption to the borehole, and have the least potential to introduce contamination. The document stipulates the use of rotary, cable tool, and auger based drilling techniques specifically. The document mandates that under no circumstances should drilling additives such as barium sulfate, polymer mud, or bentonite be used. As a general rule, a well should be designed to last at least 30 years. An analysis of the soil and rocks surrounding the well will indicate which filter packs and screen slots should be used. All monitoring wells should have an apron and a concrete cap, with the apron extending from the surface to below the frost line.

Compare and contrast the Law of Superposition and the Law of Initial Horizontality in sedimentary rocks

According to the law of superposition, one of the earliest postulations in geology, older layers of rock and sediment always lie beneath younger layers. The law of initial horizontality, meanwhile, describes the fact that geologic layers were originally deposited in horizontal layers. Although both these laws attempt to explain the original placement of sedimentary or extrusive igneous rock, initial horizontality does not imply any age relationship between beds or suggest their origins. The law of superposition, although generally true in the field, does now allow for the existence of intrusive sills, sediment dykes, or other instances of younger rocks occurring within older rocks. This law has been clarified and placed in quotation marks in modern geology by the discovery of many exceptions from many different geologic environments. The law of original horizontality is still a basic premise of geology. Certain variations to absolute horizontal sedimentation, such as flysch sequences and steep gradient alluvial fans, have been discovered but this basic law is still in force.

Discuss the most common uses for aerial photographs in geological projects

Aerial photography is very useful in the early stages of geologic investigation for planning and preliminary inspection of surface features. Aerial photography is initially used in geological investigations for terrain analysis. This branch of earth science is known as photogeology. Regional drainage patterns as seen on aerial photographs can reveal information about lithologies of rock. Disruptions in the landscape, such as landslides or sinkhole, are often highly visible on air photos. Many times these features are indiscernible on the ground without assistance of aerial photos. Stereo-paired aerial photographs are essential in geologic mapping and in the production of topographic maps. Aerial photogrpahs are especially useful in planning traverses and solving access issues prior to a geologic field investigation.

Relate intrusive, or plutonic rocks, with their extrusive, or volcanic counterparts, based on their feldspar type.

Alkali-feldspar granite is the end-member of quartz-rich plutonic rocks in terms of feldspar composition with <10% plagioclase (calcium) feldspar, and 90% to 100% alkali-feldspar (K-spar) (sodium/potassium). The extrusive counterpart is alkali-feldspar rhyolite. A progression of plagioclase/K-spar concentration ratios define a series of plutonic rocks from granite (30-90% K-spar;10-65% Plagioclase), to granodiorite (10-35% K-spar; 65-90% plagioclase), through tonalite (<10% K-spar; 90-100% plagioclase). The extrusive equivalents of these are rhyolite, dacite. Syenitoids are quartz-poor relative to granites. These rocks range from alkali-feldspar syenite (90-100% K-spar; <10% plagioclase), to syenite (65-90% K-spar; 10-35% plagioclase), to monzonite (35-65% of both plagiocalse and K-spar). The extrusive equivalents of these rocks are trachyte and latite. Most extrusive volcanic rocks are basalt that typically contains only plagioclase feldspars.

Discuss the relationships between the following terms: synforms, antiforms, downwarps, upwarps, synclines, anticlines

All of these terms describe folds. A synform is a concave fold whose limbs close downward to the fold axis in strata for which the stratigraphic sequence is unknown. If the stratigraphic sequence is known and involved in the folding, and the core of the fold contains stratigraphically younger rocks, the feature is called a syncline. A convex fold whose limbs close upward to the fold axis in strata for which the stratigraphic sequence is unknown is called an antiform. If the stratigraphic sequence is known and the core of the fold contains older rocks, the structure is called an anticline. Upwarps are any areas of the Earth's crust that have been subjected to generic upward or convex deformation short of anticlinal formation. Downwarps are any regions of the earth's crust that are concave due to structural deformation.

List the order of deposition of evaporties, and explain why they form in order.

All water bodies on the surface and in aquifers contain dissolved salts. If a body of water becomes restricted in a closed basin and inflow of fresh water is restricted such that it remains below the valve of net evaporation, dissovled salts begin to concentrate. With continued evaporation, dissolved salt concentrations may become oversaturated and minerals called evaporites will begin to precipitate out. The main groups of evaporite minerals are: Halides (halite, sylvite, and flourite), Sulfates (gypsum, barite, anhydrite), Nitrates (nitratite, niter), Borates (borax), and Carbonates (trona). Evaportie minerals start to precipitate when their concentration in water reaches such a level that they can no longer exist as solutes. These minerals will precipitate out of solution in reverse order of their solubilities. The order of precipitation of the evaporte minerals is: 1) calcite and dolomite, 2) gypsum and anhydrite, 3) halite, and 4) potassium and magnesium salts.

Distinguish between the following terms: aquifer, confined aquifer, unconfined aquifer

An aquifer is defined as an underground stratum or zone below the surface of the Earth capable of producing water. The zone must yield water in sufficient quantity to be of value as a source of supply. In an unconfined aquifer the system is open to exchange as the upper boundary of the aquifer is at the water table or phreatic surface. Usually the shallowest aquifer at a given location is unconfined, meaning it does not have a confining layer (an aquitard or aquiclude) between it and the surface. Unconfined aquifers are readily recharged by rainfall, streams and lakes which are in hydraulic connection with it. A confined aquifer has the water table above its upper boundary (an aquitard or aquiclude), and are typically found below unconfined aquifers.

Discuss the elastic properties that an object may have, and how they are measured

An elastic material is one that changes shape in response to any stress, but immediately reverts back to its original shape when the stress ends. The relationship between stress and strain can be quantified with Poisson's ratio, Young's modulus, the shear or rigidity modulus, or the bulk or incompressibility ratio. Poisson's ratio is the comparison of the change in length divided by the change in diameter. Young's modulus is calculated as normal stress divided by axial strain in cases where the stress-strain ratio is constant. The bulk or incompressibility modulus is calculated as hydrostatic pressure divided by volumetric strain, and is used in cases where pressure is uniform on the object in all directions. Bulk modulus is the inverse of compressibility, and shear modulus is calculated as shear stress divided by shear strain.

Discuss how unconfined aquifers are filled and emptied

An unconfined aquifer is by definition an aquifer that has an open upper boundary coinciding with the water table. Thus, unconfined aquifers are often referred to as water table or phreatic aquifers as they do not have confining aquitard or aquiclude layer between them and the surface. An unconfined aquifer receives recharge water directly from surface precipitation, or from a body of surface water, such as a lake or stream, that is in hydrologic conductivity with it. Unconfined aquifers have relatively high storativities and hence release water from storage by the mechanism of actually draining the pores of the aquifer, releasing relatively large amounts of water. This can occur through extraction from surface or underground wells and/or loss to a deeper confined aquifer through seepage

Explain what an unconformity is, and what kind of information it provides

An unconformity is an interruption in the normal sequence of the geologic record. An unconformity is frequently an erosion surface that is buried by younger sediments in a reactivated area. Frequently, it is not possible to determine exactly what amount of time an unconformity comprises, though an estimate can be made by determining the ages of the surrounding rocks. An unconformity ca be millimeters in thickness yet represent a great amount of missing time. A sedimentary rock package can contain numerous unconformities such that the rock record is very incomplete. An unconformity typically indicates erosion, non-deposition, or regional uplift. Unconformities provide specific information about the geologic history of a region including tectonic events, sedimentation patterns, and basic histories.

Describe the three classifications of grain size in crystalline rocks: aphanitic, phaneritic, and porphyritic, and link grain size with rock origin.

Aphanites are igneous rocks in which the individual mineral grains cannot be discerned with the naked eye. An aphanitic texture in igneous rocks indicates rapid cooling. This is commonly observed in extrusive rocks such as lavas or near-surface intrusive rocks such as sills and dikes. Phanerites are relatively large-grained intrusive rocks in which individual mineral grains can be discerned and described with the naked eye. Phaneritic texture in igneous rocks is caused when magma is trapped underground and allowed to cool slowly, facilitating larger mineral growth. Phaneritic texture characterized by large interlocking grains of different minerals is commonly seen in plutonic rocks such as granites. Porphyritic textures are observed in many plutonic rocks and contain both previously described textures: large megascopic minerals are surrounded by a fine groined groundmass in which minerals cannot be discerned with the naked eye (microscopic). Porphyritic textures occur in plutonic rocks when a magma is allowed to partially cool at a slow rate, generating some large mineral grains, and then rapidly cooled to produce the aphanitic groundmass.

Review which aquifer properties, such as porosity, yield, storativity, conductivity, permeability, and hydraulic graident, affect the flow of ground water

Aquifers are typically saturated regions of the subsurface which produce an economically feasible quantity of water. Many quantified aquifer parameters affect the flow of groundwater while others desccribe aquifer volume and storage capacity. Specific storage, storativity, specific yield, and specific capacity are aquifer properties that measure of the ability of an aquifer to release groundwater from storage due to a decline in hydraulic head. These properties are related to groundwater flow in aquifers but do not directly affect groundwater flow. Other aquifer properties such as porosity have to do with the ability of the aquifer to store water. The parameters that describe the ability of ground water to flow through an aquifer are transmissivity, hydrualic conductivity, and intrinsic permeability. These factors are regulated by the differences in the potential energy of the groundwater, which in turn are a factor of the water distribution. These and several other attributes are used to derive the groundwater flow equation, a mathematical relationship used to describe the floe of groundwater through an aquifer

Compare the porosities of common sediments and rocks, such as clay, sand, gravel, sandstone, shale, and basalt

As grain size increases and sorting decreases, porosity tends to decrease. For this reason, materials like clay and silt are considerably more porous than materials like glacial till. Consolidation of geologic materials into rock tends to decrease porosities as rock grains are cemented together during diagenesis. Thus, shale has a porosity of between 0 and 10% and fractured crystalline rock has a porosity of between 0 and 10%. Limestone has a porosity of between 1% and 20%. Sandstone has a porosity of between 5% and 30%. Glacial till has a porosity of between 10% and 25%. Sand has a porosity between 25% and 40%, as does gravel. Silt has a porosity of between 35% and 50%. Clay has a porosity of between 45% and 55%.

Explain what landslide stability analysis methods involve, and what their function is.

As part of a landslide investigation, a landslide and stability analysis will be performed in order to calculate what is known as the factor of safety (F). The factor of safety is simply the ratio of the forces that will resist a landslide divided by the forces that will promote a landslide. The factor of safety (F) is the likelihood of a landslide occurring in a particular area. In order to perform this analysis, a geologist will need to ahve an equilibrium slope analysis, a measure of the sheer strength of local soil, and the general idea of the orientation and angle of internal friction of the subsurface materials. In many cases, it will be possible to perform a landslide stability analysis by using a general slope stability chart.

Quantitatively review the classifications of water hardness, from soft to very hard, and how water hardness affects its use and the structures containing it

Because it is the precise mixture of minerals dissolved in the water, together with the water's pH and temperature that determines the behavior of hardness, a single-number scale does not adequately describe hardness. Descriptions of hardness correspong roughly with ranges of minerla concentrations. Hardness concentration is described in the unit's milligrams per liter (mg/L). Water with dissolved mineral concentrations from 40 to 60 mg/L is classified as slightly hard. If dissolved mineral concentrations increase to the 60 to 80 mg/L range the water is classified as moderately hard. Hard water contains concentrations in the range 80 to 120 mg/L. Very hard water contains dissolved mineral concentrations exceeding 120 mg/L. Hard water causes scaling, which is the precipitation of minerals to form a deposit known as limescale. Scale will clog pipes, ruin water heaters, coat the insides of tea and coffee pots, and decrease the life of toilet flushing units.

Describe the geologic map symbols used for bedding and joints

Bedding attitude, composed of the strike and dip of a particular bed, is indicated with a T shaped symbol. The top crossbar is oriented on the strike of the bedding, with the tail of the T showing the direction of dip. Usually, a numeral accompanies the symbol to indicate the degree of dip. If the bed is overturned, the tail of the T is curled back over the crossbar, with dip degree indicated. Approximate strike and dip are denoted by a dashed T. The strike of a vertical bed is denoted by a cross that is long on one side. Horizontal beds are indicated by a circled cross. An apparent dip is denoted by an arrow with a filled circle at the terminus. The strike and dip of a joint is denoted by a line with a square at one side. The line is oriented to reflect joint strike. The strike of a vertical joint is denoted by a line bisected by a filled rectangle. A horizontal joint is indicated by an X with a filled square at the center.

Compare and contrast specific yield and effective porosity, and describe how specific yield is calculated

Both specific yield and effective porosity are expressed as the ratio of the volume of water that drains from a saturated rock or soil to the total volume of that rock or soil. Specific yield is very similar to effective porosity in an unconfined aquifer. The main difference is that specific yield is found by measuring the amount of water that drains from the rock, rather than measuring the weight of the rock after drainage. Specific retention is a ratio reflecting the amount of water a soil can retain after drainage. Specific yield and specific retention can be calculated with the following equations: Sy = Vwdrained/Vt Sr = Vwretained/Vt where Sy and Sr are the specific yield and specific retention, Vw(drained) and Vw(retained) are the volumes of water drained and retained after gravity drainage of saturated soil or rock, and Vt is the total volume of the material (including the void space). Sy and Sr can also be added to yield porosity: Sy + Sr = n

Discuss Bowen's Reaction Series

Bowen's Reaction Series is based on the theory that basalt is the parent material that gives rise to all other kinds of igneous rock. The diagram below displays the progression in Bowen's Reaction Series showing the order in which minerals precipitate in an igneous melt: Olivine Anorthite Mgpyroxene/Labradorite Mg-Ca pyroxene/Andesite Amphibole/Oligoclase Biotite/Albite Potassium feldspar Muscovite Quartz The left branch is called the discontinuous reaction series and represents a collection of minerals that interact with magma to create each successive member. On the right side, the continuous reaction series, feldspar crystals perpetually interact with cooling magma. All the minerals atop the diagram are those that crystallize early, while the minerals at the bottom only crystallize once magma has cooled considerably. Bowen realized that both sides of the reaction series operate simultaneously within a cooling melt and can explain many features observed in igneous rocks.

Discuss the pros and cons of Bowen's theory

Bowen's reaction series is based on a number of controlled laboratory experiments and provides a generalized progression of mineral precipitation from a cooling magma. It is very useful in describing observed field relationships of igneous rocks and has been repeatedly verified. An importatn practical use of Bowen's theory is the prediction of mineral weathering. This is based on the fact that the surface on the Earth is a low temperature environment compared to that found during rock formation. Because of this, Bowen's reaction chart also indicates the stability of minerals at the earth's surface with the ones at bottom being most stable and the ones at top being quickest to weather. This is because minerals are most stable in the conditions closest to those under which they had formed.

Discuss the major geologic considerations that must be dealth with to site a dam, and how a proper geologic investigation would be conducted to build one

Building a dam to hold back a water reservoir is an enormous engineering endeavor. A river diversion is typically required involving coffer dams and construction site de-watering before construction of the dam can begin, a major project in itself. Rock scaling and wall preparation must be performed upon the canyon walls where the dam is located. Beforehand, geologists spend many hours analyzing aerial photographs, geologic maps, photogrammetric data, core drill data and logs, and results of engineering tests on the rocks hosting the dam site. Test would include shearing and compression tests on rock near the dam and fracture and detailed structural analyses of rocks in and around the dam site. Any dam investigation must contain a very detailed and specific earthquake and prior tectonic evaluation of the dam site and environs.

Explain Archie's Formula, and review what it is used for

Calculation of oil reserves requires determination of reservoir oil holding abilities and extraction dynamics. This involves the calculation of the water/oil percentage utilizing Archie's Formula. Archie's Formula is used to determine the water saturation of oil reserves. It is a function of porosity, resistivity, and various coefficients, and is expressed as follows: Sn/w = aRw/(phi^m)(Rt) = Fr* Rw/Rt where Sw is the water saturation, a is a constant (often 1), phi is the porosity, Rw is the resistivity of formation water when 100% saturated, Rt is the true formation resistivity, m is the cementation component, n is the saturation exponent. If water saturation is less than 60%, their reservoir will mostly provide water; with a water content of between 35 and 90% however, the reservoir may produce oil.

Discuss the different grades of coal, and rank them as a function of increasing metamorphism.

Coal is organic material that has been lithified by being pressurized and heated without oxygen over a long period of time. In general higher degrees of metamorphism produce higher degrees of coal. The types of coal are: lignite, sub-bituminous, bituminous, and anthracite. Lignite is coal of low rank with a high inherent moisture and volatile matter content. Lignite is subdivided into black lignite, brown lignite, and brown coal. Sub-bituminous coal is of intermediate rank between lignite and bituminous. Bituminous coal ranks between sub bituminous coal and anthracite and contains more than 14% volatile matter (on a dry, ash free basis) and has a calorific value of more than 11,500 Btu/lb. Anthracite is coal of the highest metamorphic rank, in which fixed carbon content is between 92% and 98%. Anthracite is hard and black, and has a semi metallic luster and semi conchoidal fracture.

Explain the formula used to estimate coal tonnage in a reserve. Discuss how much coal is available in the United States.

Coal reserves are that part of the reserve base that could be economically extracted or produced at the time of determination. The term reserves need not signify that extraction facilities are in place and operative. Reserves include only recoverable materials. The tonnage of coal in a reserve is calculated with the following equation: Tonnage = t*w*A, in which t is the weighted average thickness of coal, w is the weight of coal per unit volume, and A is the area of the coal deposit. Available coal in the United States as reported by The United States Department of Energy is 1,081,279 million short tons (9.81 x 10^14 kg), which is about 4,786 BBOE (billion barrels of oil equivalent)

Explain how cohesionless soils or soils with apparent cohesion behave in direct shear tests, and why this occurs

Cohesion is the component of shear strength of a soil that is independent of interparticle friction. In soils, true cohesion is caused by electrostatic forces, cementing, or through cohesion by contained plant roots. Apparent cohesion is caused by capillary pressure and pore pressure. Depending on the initial void ratio of a soil, the material can respond to loading by either strain-softening or strain-hardening. Strain-softened soils may be triggered to collapse if the static shear stress is greater than the ultimate or steady state shear strength of the soil. In this case, liquefaction occurs. Soil liquefaction describes the behavior of loose saturated cohesionless soils which go from a solid state to having the consistency of a heavy liquid as a consequence of increasing porewater pressures.

Review the general procedure for compaction testing of soil, and discuss how the resulting data is interpreted

Compaction is the process of increasing the bulk density of a soil or aggregate by driving out air. For any soil the density obtained through compaction depends on the moisture content. At very high moisture contents, the maximum density is achieved when the soil is compacted to saturation with msot or all of the air beign driven out. At low moisture contents, the soil particles interfere with each other and the addition of some moisture will allow for a greater bulk densities. Peak density occurs at the point at which this effect begins to be counteracted by the saturation of the soil. The procedures for compaction testing include: The Proctor test, which used a 4-inch diameter mold holding 1/30th of a cubic foot of soil that is compacted in three separate lifts of soil using 25 blows by a 5.5 lb hammer falling 12 incehs; and the Modified Proctor Test, which uses the same mold, but uses a 10 lb. hammer falling through 18 inches, with 25 blows on each of five lifts

Explain what types of geologic features could be represented by a mapped outcrop pattern that consists of concentric circles.

Concentric circles on a geologic map indicate structural deformation of sedimentary rocks by doming, sagging, or dispirism. A convex erosional feature in horizontal strata would produce a concentric-ringed "shield" pattern in outcrops, as would a concave conical depression in the same horizontal strata. For a conical hill or mountain in horizontal strata, the innermost ring in the outcrop pattern would represent the youngest rock, whereas in a depression, the center rocks of the ring outcrop pattern are the older rocks. This relationship would be invalidated if intrusive bodies were involved. A salt dome or intrusive pluton or batholith can cause a concentric circled pattern in sedimentary rocks on a geologic map after exposure by erosion. A circular pattern on a geologic map could also be caused by a meteorite impact in horizontal strata.

Describe the structure and characteristics of confined aquifers

Confined aquifers have the water table above their upper boundary and are typically found below unconfined aquifers. Usually some impermeable layer, such as an aquitard or aquiclude, prohibits hydrologic conductivity between confined aquifers and the open, phreatic aquifers above. Frequently a confined aquifer can best be recognized through the aquifer test which yields a low storativity value. This indicates that the aquifer is storing water using the mechanisms of aquifer matrix expansion and the compressibility of water, both of which are relatively quite small compared to unconfined aquifers. Discharge and recharge for confined aquifers is typically much slower than for unconfined aquifers. It is typical for the pressure inside a confined aquifer to be higher than the atmospheric pressure

Compare and contrast conventional tunneling and boring or continuous excavation methods of tunneling

Conventional methods of tunneling involve drilling and blasting. After each shot, the broken rock (muck) at the face must be removed and any timbering completed before the next shot can be drilled. These methods are preferred for hardrock mining. After the tunnel has been established structures like arches and rock bolts must be created to maintain the tunnel structure. In continuous mining a machine cuts or rips coal from the face and loads it onto conveyors or into shuttle cars in a continuous operation. This eliminates the drilling and shooting operations of conventional mining. Continuous mining provides a continuous flow of ore and eliminates the need for multiple heading in conventional technique to acheive the same. This method is more applicable to coal mining.

Discuss the characteristics that reservoir rocks must have in order to store petroleum, and explain the related concepts of porosity and permeability

Conventionally, in order for a reservoir to be capable of storing petroleum, the rocks comprising the reservoir must be porous. Porosity is defined by the ratio, P, expressed as a percentage of the volume, Vp, of the pore space in a rock to the volume, Vr, of the rock, the latter volume including rock material plus the pore space; P = 100 Vp/Vr. It is typical for a reservoir rock to have a porosity value between 10 and 20%. It is possible for some reservoir rocks to have a secondary porosity. The permeability rating of a reservoir rock must be between five and 1000 millidarcies. Permeability (or perviousness) of rock is its capacity for transmitting a fluid. Degree of permeability depends upon the size and shape of the pores, the size and shape of their interconnections, and the extent of the latter. It is measured by the rate at which a fluid of standard viscosity can move a given distance through a given interval of time. The unit of measure for permeability is the Darcy.

Discuss how rock coring differs from soil coring

Core drilling in rock involves the advancement of a 10 ft long barrel inside of the drill rod. The core barrel is attached directly behind the drill bit allowing for collection of a continuous rock sample.The bit is composed of industrial diamonds set in a soft matrix that slowly wears down as the bit advances, exposing new diamonds. Hardness of bit matrix and diamond proile is changed to counteract different drilling condition encoutnered between formations or rock types. The bit is mounted on a drill stem that is connected to rotary drill on the surface. Diamond bits are usually designed for a specific rock type and contain channels which allow for the evacuation of cuttings. Collecting an undisturbed soil sample requires the use of a cylindrical sampler. Samples are obtained by the extraction of soil cores, typically of the diameter 1-1/2 in or 4 in. The core barrel is detachable and is capped so the core is hermetically sealed for delivery to the laboratory. Individual soil cores, up to 3 ft in length may be obtained by continuous coring if necessary.

Discuss how a Mohr circle is used to evaluate stresses acting on an object

Coulomb's hypothesis determines the combination of both shear and normal stress required to cause the fracture of a material. Mohr's circle is used to determine which principal stresses that will produce this combination of shear and normal stress, and the angle of the plane in which this will occur. Normal stresses are plotted on the x-axis while shear stresses are plotted on the y-axis. The center point of the circle is the normal stress, and the radius is the maximum shear stress. A Mohr circle is formed by drawing a diagram of the object and all the stresses that are acting upon it. The diameter of the Mohr circle is determined by the maximum and minimum principal stresses. Any plane that is drawn through the object in question will lie in some relation to the major principal plan; the angle of relation is called the Mohr circle plot. The Mohr's circle is used to find the planes of maximum normal and shear stresses, as well as the stresses on known weak planes.

Describe the general structure of a dam

Dams are walls to hold back water. They are typically secured at either side by an abutment. The main part of the dam will be constructed of some impervious material, with pervious areas on either side of the dam's core. The water in the reservoid being held back by the dam will be able to penetrate the pervious areas upstream. Below the dam, a cutoff trench will be dug that prevents seepage from emerging from the reservoid. In order to prevent the dam from leaking, the phreatic line must curve down and away from the reservoir heights on the upstream side, in the direction of the dams based on the downstream side. Water pressure relief can be furnished by blanket and toe drains at the base of the previous zone, as well as by further relief wells beyond the toe drain.

Explain the principles behind Darcy's law, describe the law, and explain what it is used for

Darcy's Law is an equation that describes fluid flow through a porous medium. Darcy's Law forms the scientific basis of fluid permeability in earth sciences. Darcy's Law is essentially a proportion between the instantaneoud discharge rate through a porous medium and the viscosity of the fluid and the pressure drop over a given distance. The equation for Darcy's Law is as follows: vd = K * h1-h2/l = Q/A where vd is the specific discharge or discharge velocity, K is the hydraulic conductivity, (h1-h2)/l is the hydraulic gradient, Q is the volumetric discharge rate, and A is the cross sectional area of the open space of the pipe. This law is used to calculate the speed with which water can move through an aquifer, especially a confined aquifer. Darcy's Law can only be used in situations of low turbulence and slow flow.

Discuss how Darcy's Law must be modified for steady flow in an unconfined aquifer

Darcy's Law is used to establish ground water flow equations essential for calculating fluid movement in confined aquifers. These groundwater flow equations are valid for three dimensional flow only. In unconfined aquifers, the solution to the 3D form of the equation is complicated by the presence of a free surface water table boundary condition. Problems arise because in addition to solving for the spatial distribution of heads, the location of this surface is also an unknown. This is a non linear problem, even though the governing ground water flow equation is linear. Hence, Darcy's Law must be modified using the Dupuit assumption.

Discuss the ways density is tested, and explain why these are examined

Density is a property of particulate materials defined as the mass of the particles of a given volume divided by the volume that they occupy. There are a number of different techniques to test for density in soils. The Proctor Compaction Test and the simialr Modified Proctor Compaction Test are utilized to ascertain the maximum acheivable density of soils. The Proctor Compaction Test (ASTM D698) uses a 4-inch diameter mold holding 1/30th of a cubic foot of soil. The soil is compacted in three separate lifts using 25 blows by a 5.5 lb hammer falling 12 inches. This delivers an effective compactive effort approximately 12,4000 ft-lb/ft^3. The Modified Proctor Compaction Test (ASTM D1557) utilizes the same mold as the Proctor Compaction test, but differs in the use of a 10 lb hammer falling through 18 inches with 25 blows on each of the five lifts. This achieves an effective compactive effort approaching 56,000 ft-lb/ft^3. There is also a test (ASTM D4253) which uses a vibrating table using standard vibrations for a standard time to densify the soil

Distinguish the field determined categories of rock strength

Determination of rock strength in the field involves assessing its hardness, fracturing, porosity, and the degree to which it has been weathered. Field assessments of rock strength are generally subjective, as opposed to the very stringent and objective rock strength tests performed in a laboratory setting. Standardized field tests to measure rock strength involve the use of a 2 pound hammer strike a 4 inch thick sample. The reaction of the rock to the hammer strike allows the geologist to place the rock on the spectrum of strength ranging from very weak to very strong. A very weak rock will crumble when it is pressed with a finger. A moderately strong rock can be hit with a hammer a few times before it breaks. A strong rock can be hit very hard a few times without breaking, and when it breaks, will break into large pieces. A very strong rock can be hit very hard without breaking.

Review how weathering and erosion create a diverse array of sedimentary products.

Detritus, consisting of fragments of rocks and minerals, is moved by the surface processes of weathering and erosion. Moving particles drop out when the energy of transportation drops below that needed to carry these particles. This is known as clastic sedimentation. Another common type of sedimentary deposition occurs when material that is dissolved in water precipitates out to from sediment. This type of sedimentation is known as chemical sedimentation. A third process involves living organisms which extract ions in water to construct shells and bones. This material collects after the death of the organism and is described as biogenic sedimentation. Most of all sedimentary rocks (95%) consist of sandstones, mudrocks (made up of silt and clay-sized fragments), and carbonate rocks (made up of mostly calcite, aragonite, or dolomite). Weathering and erosion release all of these materials to be re-incorporated into new sedimentary rocks.

Define diagenesis, and list the types of diagenetic processes

Diagenesis is any change occurring within sediment after its deposition and during and after its lithification, exclusive of weathering. It includes such processes as compaction, cementation, replacement, and crystallization, under normal surficial conditions of pressure and temperature. Compaction and lihtification are both considered to be diagenetic processes, but weathering and metamorphism are not as they do not occur between 100 and 300 degrees celsius. The following are other diagenetic processes: 1) cementation, the diagenetic process by which coarse clastic sediments become lithified or consolidated into hard, compact rocks, usually through deposition or precipitation of minerals in the spaces among the individual grains of the sediment. 2) replacement, change in composition of a mineral or mineral aggregate, presumably accomplished by diffusion of new material in and old material out without breakdown of the solid state

Material can be radiometrically dated by many methods, each of which is appropriate for a different age range. List the radiometric methods and the appropriate age window in which they can be used.

Different radiometric methods for age-dating material are available according to the range of ages believed for the material to be tested. Radiometric dating utilizes known rates for the decay of unstable elements into stable daugther elements and the ratios of relative abundances of these isotopic species within a sample. Carbon-14 or radiocarbon dating is used to date organic material up to 60,000 years old. Potassium-argon isotope dating is used to date geologic materials greater than 100,000 years in age. Uranium-thorium dating is used to date carbonate materials that are younger than about 500,000 years. Rubidium-strontium isotope dating is a whole rock dating technique used for igneous materials over 10 million years old. Uranium-lead isotopes are used to date geologic materials between 1 million and 4.5 billion years olf. Radiometric age dating is typically referred to as absolute age dating because a specific age or range of ages is obtained.

Discuss what disinfection byproducts are, and how they become contaminants in groundwater

Disinfection byproducts are chemical substances that form during reactions between disinfectants and organic matter in groundwater. Chemical disinfection of drinking water with substances such as chlorine has been practiced for more than a century. Disinfection byproducts have been deemed to be harmful to human health. The types of disinfection byproducts that form depend on a number of factors. Interaction of different types of disinfectants, and residence times within groundwater aquifers are determining factors in byproduct speciation. Temperature and pH of groundwater also affect byproduct formation. High residence times of disinfectants produce more byproducts. With shorter residence times, higher concentrations of trihalomethanes (THM) and halogenic acetic acids (HAA) are formed. When residence times are longer the temporary forms of disinfection byproducts may become disinfection endproducts, such as tribromine acetic acid or bromoform.

Give the distance-drawdown test equations for calculating transmissivity and storativity.

Distance-drawdown test equations: For calculating transmissivity in square feet per day: T = 70Q/ds For calculating transmissivity in gallons per foot per day: T = 528Q/ds For calculating storativity in square feet per day: S = Tt/640r0^2 For calculating storativity in gallons per foot per day: S = Tt/4790r0^2 where Q is pumping rate, ds is the change in drawdown (over one log cycle from the plot), t is the time since testing began, and r0 is the distance from the pumping well at the beginning of testing.

Compare and contrast the following sedimentary rocks: dolomite, diatomite, chert, pyrite, peat, coal, and evaporates.

Dolomite, known chemically as CaMg(CO3)2, forms when the porewaters in limestone are enriched through evaporation which causes magnesium to be subsequently excahnged for calicum in the atomic structure. The formation of diatomite, a light-colored soft friable siliceous sedimentary rock consisting chiefly of diatoms, occurs through thick accumulations of diatomaceous material (diatomaceous earth). Chert is a hard dense, dull to semivitreous, microcrystalline or cryptocrystalline sedimentary rock, consisting dominantly of interlocking crystals of quartz. Chert may also contain amorphous silica (opal). Pyrite is not a sedimentary rock. It is a sulfide mineral. Pyrite frequently occurs diagenetically in marine shales. Peat is formed in swamps from accumulation of dead and partly decomposed marsh vegetation. Peat has a yellowish brown to brownish black color, is generally of the fibrous consistency, and can be either plastic or friable. Coal is a readily combustible rock containing more than 50% by weight and more than 70% by volume of carbonaceous material.

Explain why drilling fluid additives are used in boreholed, and discuss the purposes of various additives.

Drilling fluid, called drilling mud, is used in rotary drilling and is pumped down through the drill stem. Drilling mud is a water-based, chemical or physical suspension that seals off porous zones and suspends and disperses drill cuttings. Drilling fluid also counteracts the pressure of formations encountered in drilling. It consists of various substances in a finely divided state including bentonite and barite. Barite or other weighting matericals are used to counterbalance formation pressure and to stabilize the borehole. Calcium carbonate or ground cellulose can be used as bridging agents to seal gaps in very porous formations by allowing the formation of a filtercake against the sides of the borehole. Bentonite, gilsonite, artificial polymers, or asphalt are used as additives to improve filtercake properties. Chemical inhibitors can be used to counteract adverse reactions between drilling fluid and certain formations. This is most commonly used when drilling in shale-rich formations when calcium, potassium, salts, polymers, asphalt, or glycol are added to counteract these reactions.

Explain the general characteristics of dunes and the four subtypes of dunes, and connect environmental conditions with the resultant dune structure

Dunes are large wind-derived accumulations of sand that are located anywhere there is a source and a mode of emplacement, such as beach or desert environments. There are four basic types of dune: - parabolic dune: U-shaped mounds of sand with convex noses and elongated arms. Sometimes these dunes are called blowout or hairpin dunes and are well known in coastal deserts. Unlike crescent shaped dunes, their crests point upwind. The elongated arms of parabolic dunes follow rather than lead because they have been fixed by vegetation - transverse dune: barhan dunes - longitudinal dune: longitudinal dunes, also called Seif dunes, elongate parallel to the prevailing wind, possibly caused by a larger dune having its smaller sides blown away, Seif dunes are sharp-crested and are common in the Sahara -barchan dune: crescent-shaped mounds are generally wider than they are long. The slip face is on the dune's concave side. These dunes form under winds that blow from one direction, and they also are known as transverse dunes

Describe how the stratigraphic succession of geologic units would be identified during analysis of a geologic map

During the analysis of the geologic map, there are a few different ways that the stratigraphic succession of geologic units can be identified. The first and best way is by consulting the stratigraphic key that accompanies every geologic map. The key is a graphic representation of the rock units on the map, their names and ages, and their relative stratigraphic positions. If no key is available, the topographic lines on the map must be used to ascertain how stratigraphic units crop out on the surface. For example, units on the map that occur concentrically around the bases of hills etc., are generally older and deeper than inner rings units farther up a hill. Many geologic maps contain symbols that indicate the attitude of a bedding that can be used to determine stratigraphic relationships. There are also generally agreed standards for selected colors of known classification and ages of rocks on many geologic maps allowing the user to see stratigraphic relationships in a glance.

Disucss the different types of magnitude scales used to measure earthquakes and the unique characteristics of each one

Earthquakes are caused by a sudden release of enery from the Earth's crust. Earthquakes are recorded with a seismometer, also known as a seismograph. There are a few different magnitude scales used to measure earthquakes. The Richter scale, also known as the local magnitude scale, utilizes a single number system to quantify the seismic energy released by an earthquake. It is a base-10 logarithmic scale obtained by calculating the logarithm of the combined horizontal amplitude of the largest displacement from zero on a seismometer output. There are other types of magnitude scale, including individual scales for surface waves and body waves. The Mercalli and Rossi-Forel scales measure the intensity of an earthquake by assessing its effects on structures and human beings. Intensity of shaking is measured on the modified Mercalli scale.

List the equations used to calculate seismic moment (M0), moment magnitude (M), and earthquake energy release (Er)

Earthquakes are recorded with a seismometer, also known as seismograph. Earthquakes are also measured and described by the following physical characteristics: seismic moment is calculated with the following equation: M0 = mew*A*u where M0 is seismic moment in dyne-cm or N/m, mew is the shear modulus of the crustal segment containing the fault, A is the fault area of interest, and u is the average slip along the fault. Moment magnitude is calculated with the following equation: M = logM0/1.5 - 10.7 Energy release (Er) is calculated with the following equation: Er = 1.6M0 * 10^-5

Distinguish between effective porosity and true porosity. Explain how effective porosity is determined.

Effective porosity of a geologic material is expressed as the ratio of the volume of liquid that a given mass of saturated rock or soil will yield by gravity to the volume of that mass. True porosity is the measure of all the existing voids in a rock or soil. Effective porosity is simply the measure of those voids through which a fluid can flow. In all cases, effective porosity will be lower than true porosity. The equation used to calculate the effective porosity is as follows: ne = Ws-Wr/Ws-Wo * Vv/Vt where ne is the effective porosity, Ws is the weight of a saturated soil sample, Wr is the weight of the sample after gravity drainage, Wo is the weight of the air dried sample, Vv is the volume of void space, and Vt is the total volume of the material (including the void space).

Explain the applications of electrical resistivity in geological investigations.

Electrical resistivity logs are used to obtain information about the composition of materials below the surface, as well as the geologic structures underground. Resistivity measurements can be performed as a downhole survey or from the surface. The method for surface resistivity is to apply electrodes directly to the ground. By comparing the difference in potential voltage between two different electrodes, the difference in potential voltage between two different electrodes, information about ground water depth, ground water contamination, horizontal extent of conductive contaminants, vertical extent of soil, stratigraphy, and the presence of clay aquitards may be determined.

Describe what epigenetic deposits are and how they can come from "doubtful" igenous origins

Epigenetic ore deposits are those that were formed subsequently after the rocks which host them. The term is the opposite of syngenetic deposits which were formed at the same time as the host rocks containing the deposits. Seafloor exhalative deposits or magmatic segregation deposits are examples of mineral occurrences that are syngenetic as the minerals were laid down at the same time as the host rocks. Epigenetic deposits are not directly related to the formation of the rocks which host them but frequently are due to some secondary connection to host rock formation. An example would be cooling history of a granite that controls fracturing to be later filled with hydrothermal minerals. Some examples of epigenetic deposits include: hydrothermal deposits and sediment hosted uranium deposits.

Distinguishing between the following pointed glacial features: arete, col, horn, monuments/tinds, and truncated/faceted spurs

Erosion due to alpine glaciation and cirque development causes some steep landforms at poitns where cirques intersect. Some of Earth;s most spectacular mountain scenery occurs in glaciated areas with these steep and pointed features. The following are pointed features of a glacier: - arete: a knife edged rock divide between two glacial cirques - col: a connection across the rock arete dividing two cirques - horn: a peak or pinnacle thinned and eroded by three or more glacial cirques. The Matterhorn of the Swiss Alps was formed in this manner - monuments/tinds: a horn that has been separated by itself by intersecting cirques - truncated/faceted spurs: triangular hillside features due to galcial erosion of the headlands between two former streams

Discuss what causes expansive soils, and how they can be identified and mitigated

Expansive soils, referred to as swelling soils, are those that assume a general volume increase when subjected to moisture. Swelling soils always contain clay minerals that readily attract and absorb water. Another type of swelling material is known as swelling bedrock, containing rock called claystone. When water is absorbed these clays or bedrock experience a large increase in internal pressure or an expansion of volume. In many cases, expansive soils are buried under a layer of topsoil or dense vegetation and cannot be identified at the surface. Test holes can be drilled by geotechnical and civil engineering firms or by some construction companies to collect samples. After the samples are taken, they are sent to a laboratory where the swelling potential is determined. In areas where there is a high concentration of swelling soils, laboratory analysis of the soil is required by law. Mitigation of expansive soils invovles dewatering foundations in existing and designed structures.

Discuss what facies are, and how they relate to depositional environments

Facies is a term of wide application, referring to such aspects of rock units as rock type, mode of origin, composition, fossil content, or environment of depositon. A facies change refers to a lateral or vertical cariation in the lithologic or paleontologic characteristics of contemporaneous sedimentary deposits. It is caused by, or reflects, a change in the depositional environment. Facies may change vertically through a sequence as a result of changing environment through time. Facies may also change laterally through a deposit as a result of changing environments with distance at the same time. The structures and textures found in sedimentary rocks give clues to the environment of deposition, as discussed above, and thus allow geologists to assign parts of a deposit to a particular sedimentary facies. Individual facies are generally described in terms of the environment in which deposition occurred.

Describe how faults can be identified on a map, using either stratigraphic or geomorphic fault indicators

Faults on geologic maps can be identified by using stratigraphic or geomorphic fault indicators. Stratigraphic fault indicators tend to be more reliable, since geomorphic fault indicators may be caused by rock movements that are not related to faults. The most common stratigraphic fault indicators are structural discontinuities, neighboring noncotiguous sedimentary facies, and repeating or missing bedding. Large scale faults with significant displacements are recognizable on maps as these faults bring rocks of different units or formations into contact across their traces. Large-scale fault movement produces deformation or folding in both headwall and footwall rocks recognizable as drag folds. These features are recognizable as variations in the mode of normal stratigraphy. Although erosion cna obscure faulting, stratigraphic clues such as repeated or inverted bedding, or missing portions of known sections, can indicate faulting. In areas of thrust faulting, thrust-bend-folding or stacked thrust sheets with repeated stratigraphic sections are indicators of regional faulting.

Both physical and biological features can be used to locate the top of bottom of a bed. Discuss the features formed by each process and how they can help orient a bed

Features that orient a bed are often referred to as top and bottom indicators. As sedimentary rocks can be deformed by folding and faulting long after the depositon process has ended, it is importatn to be able to determine which was up in the rock when it was originally deposited. Original depositional features such as cross-bedding, graded bedding, or imbricate bedding can be useful in general reorientation of beds. Other physical structures useful for oreintation of bedding include: ripple marks (top of bed), mud cracks (top of bed), raindrop marks (top of bed), load casts( bottom of bed), sole marks (bottom of bed), and tool marks (top of bed). Biological activity after deposition can impart recognizable structures on sedimentary rocks, such as burrows and trails.

Provide descriptions for each Unified Soil Classification System subdivision of fine grained soils and highly organic soils, and include their dry strength, dilatancy, and toughness characteristics

Fine grained soils will have more than 50% of their content pass through a No.2 sieve. The subdivisions are: silt and clay with a liquid limit less than 50; and silt and clay with a liquid limit greater than or equal to 50. Both are further subdivided in organic and inorganic components. Inorganic silts and fine sands will have a very small dry strength, no toughness, and either a quick or slow dilatancy. Inorganic clay has a low to medium plasticity and will have a medium to high dry strength, a moderate amount of toughness, and little if any dilatancy. Organic silts and organic silt-clays with a low plasticity will have a slight to medium dry strength, slight toughness, and a slow dilatancy. Inorganic silts and fine sandy or silty soils will have a low level of toughness, a slight dry strength, and a slow dilatancy. Inorganic clays with a high level of plasitcity will have a high dry strength, a high degree of toughness, and no dilatancy.

Differentiate between laminar and turbulent flow, and describe where you would expect to find each type of flow

Flow of water in which the flow path remains distinct and the flow direction at every point remains unchanged with time is referred to as laminar flow. Laminar flow is characteristic of the movement of ground water. Water flow in which the flow lines are non distinct, confused, and heterogeneously mixed is referred to as turbulent flow. Turbulent flow is characteristic of surface water bodies. In turbulent flow fluid motion occurs in which random parts of the fluid are superimposed upon other random parts of the fluid, impeding a simple laminar pattern of flow. When laminar flow is occurring, all the molecules of water are basically moving in the same direction at the same rate. Turbulent flow, on the other hand, is when the water molecules move in an irregular fashion, usually because of drag either within the fluid or between the fluid and the objects that surround it. Turbulent flows are more likely to occur at high speeds, and in thinner fluids.

Describe how the scale of an aerial photo depends on focal length and altitude

Focal length is defined as the distance from the center of the camera lens to a point where the image is center on the film. The scale of an aerial photograph is determined by dividing the focal length of the camera by the altitude of the survey platform. The scale of an aerial photograph changes with collection height. In photogrammetric surveying, the platform will maintain a fix altitude over a target area so a relatively consistent scale is maintained. Because of lens distortion and elevation differences, the scale from aerial photography is not consistent from center to edge. A special kind of photo called an orthophotograph is an aerial photograph that has been planimetrically corrected to remove distortion caused by camera optics, camera tilt, and differences in elevation. Unlike an uncorrected aerial photograph, an orthophotograph can be used to measure true distances as it is an accurate representation of the earth's surface.

Describe why folded units are used on maps, and tell how to recognize fold characteristics on a map

Folds on a geologic map may be recognized both by outcrop pattern and by special map notation symbols. Typically these attributes occur together on a map and can both be used to understand geologic structure. Gentle folding in sedimentary rocks will only be recognizable by outcrop pattern if erosion has cut into the structure exposing deeper beds within a fold. Concentric or sub concentric outcrop patterns typically result. Bed thickness is also a factor in outcrop pattern in folded geology. Map symbols relating to folds consist of a line tracing the fold axis, frequently including an arrow indication plunge direction and a number value for plunge angle. The fold axis line traces the zone of zero dip or dip rollover with dips increasing laterally away from the axis. Folds may be symmetrical or asymmetrical. Geologic maps contain other symbols such as dip direction and calue of individual beds or untis and overturned bedding symbols that can be used in conjuction with fold axis symbols and outcrop pattern to understand sub-surface structure

Describe the geologic map symbols used to indicate foliation and cleavage

Foliation is a general term for a planar or sheeted arrangement of textural or structural features in any type of rock. It refers to the planar structure that is caused by flattening of the grains of a metamorphic rock. Cleavage is the property or tendency of a rock to split along aligned fractures or closely spaced planes. These foliation controlling textures are caused by deformation or metamorphism. Foliation and cleavage are indicated by a strike symbol, marked with a triangle that is oriented with dip angle noted. Horizontal foliation is denoted by a cross with a diamond at the center. Horizontal cleavage is indicated by a cross with bars at the end of each line. Cleavage generally does not include a value.

Discuss what effect fractures have on rocks

Fracturing will have an influence on both the compressive and tensile strength of a rock depending on their size, orientation, and number. Fractures also determine the relative physical weatherability of a rock as fracture density and magnitude will affect the degree to which water and freeze-thaw effects can penetrate into a sample. Fracturing also allows chemical weathering to proceed at accelerated rated within a rock sample. Fracturing can affect a rocks ability to hold water and will, along with porosity, determine a rock's ability to act as an aquifer. In similar fashion, fracturing will determine a rocks ability to be impregnanted with oil or gas, an important attribute of petroleum exploration. Fracturing is a function of lithology, thermal history, and tectonics.

Describe how to convert between map scales

Frequently it becomes necessary to work with maps with differing scales, requiring conversion from one map scale to another. The most effective method for working with differing map scales is utilization of an engineering ruler with multiple scales. The map reader can also obtain packaged individual rulers that are prepared in commonly-used map scales. These rulers typically are graudated in miles, kilometers, feet, and meters, allowing the conversion between maps with different scales at a glance. If only one scale ruler is available, the quickest way to convert between map scales is to divide the new scale by the old scale and then multiply that converstion ratio by the number of feet an inch represents on the first scale. This will give the number of feet an inch represents on the second scale. Modern computerized mapping software is pre-programmed to automatically convert between map scales, removing the need for manual conversion in many instances.

Discuss how studying facies of metamorphic rocks can help assess metamorphic conditions experienced by the rocks

Geologists often study the facies of metamorphic rocks in order to determine the pressure and the temperature at which the rocks were formed. During broad and consistent regional metamorphism, all the rocks in an area will experience varying degrees of pressure and temperature. By studying metamorphic grade zones across a region the metamorphic episode can be fully understood. In contact metamorphism, decreasing metamorphic grade outward due to temperature gradient is useful in identifying ore zones and in describing a metamorphic event. Contact metamorphism typically has a far smaller or no pressure signature compared to regional metamorphism. In dynamic metamorphism, a process in which rocks are fractured by intense pressure, metamoprhic facies can aid in interpretation of a faulting event or earth movement.

Distinguish between type locality and type section

Geologists use the expressions type locality and type section to describe the specific location, and the specific rock outcropping, respectively, that a new mineral or geologic formation was first described. A type locality is the place where a mineral or geologic feature is first found, described, and best represented. It is not uncommon for a newly discovered mineral to be named after this location, although minerals can also be named for the person who first described them or for their chemial compositions. A geologic formation, or genetically related group of sedimentary rocks, on the other hand, is assigned a name based on the specific location or area where the formation is best exposed or best represented. This is the type section. It is most often named for a town or cultural feature near to where the formation occurs. The type section more refers to a stratigraphic group of rocks that are the most typical of a depositional environment. The type locality and the type section are representative of the best example of a mineral or geologic feature.

Explain the geomorphic indicators of faults on a map, including features, chemical, and physical changes

Geomorphic features on a geologic map can indicate the general location of a fault. Large scale faults with significant displacements are recognizable on maps as these faults bring rocks of different units or formations into contact across their traces. Large-scale fault movement produces deformation or folding in both hanging wall and footwall rocks recognizable as drag folds and breccia zones. Fault or shear zones can form positive topography if they become silicified, rendering them more resistant to erosion than bounding rocks. Other map features that can indicate faulting include: scarplets, offset ridges, alignes springs, offset streams, and sag ponds. Lithological or mineralogical changes caused by faulting may be included on a geologic map. Rock debris and clay gouge material may be present indicating the fault trace. Broken and recemented breccias may indicate faulting. The actual plane of fault movement can often be observed and displacement direction measured in slickensides, an oriented crystalline mineralic coating on faces.

Explain grading and sorting, and mention the types of information these can provide

Grading and sorting refer to the distribution of grain sizes within a sedimentary rock. The relative distribution of particles sizes within a sedimentary rock indicated the depositional and post-depositional history of the sample. Graded bedding is a type of bedding in which layers display a progressive change in particle size from coarse at the base of the bed to fine at the top. It forms under conditions in which a prevailing current decliend in energy or indicated rapid sedimentary events such as in a single short lived turbidity current. Sorting is the process by which granular or fragmental with a particular characteristic such as similar size, shape, or specific gravity are selected from a larger mass. Sorting can indicate post-depositional redistribution of mineral grains or reveal spatial variations in a depositional redistribution of mineral grains or reveal spatial variations in a depositional system dependent upon distance from source.

Describe how the grain shapes of rocks are described, and how this relates to rock surface texture

Grain shape, or more accurately, mineral boundary interaction, in an igneous rock sample is described by the terms euhedral, subhedral, or anhedral. A euhedral mineral grain is completely bounded by its own rational faces indicating that the minerals growth during crystallization or recrystallization was not restrained or interfered with by adjacent grains. Full euhedral crystal specimens of minerals are prized by mineral collectors. A subhedral mineral grain is bounded partly by its own rational faces and partly by surfaces formed against preexisting grains as a result of either crystallization or recrystallization. Anhedral textures occur in igneous rocks when mineral grains are not bounded by their own crystal faces but have an imperfect form impressed on them by the adjacent minerals during crystallization.

Review the geological uses of ground-penetrating radar.

Ground Penetrating Radar (GPR) can be used in a variety of geologic and engineering media, including rock, soil, ice, fresh water, pavements and structures. It can detect objects, changes in material, and voids and cracks. Ground Penetrating Radar has many applications in a number of environmental and engineering fields. It is used to study bedrock, soils, groundwater, ice and also has a number of engineering applications. Non-destructive testing of structures and pavements, locating buried structures and utility lines are included. In environmental remediation GPR is most often performed to delineate landfills and contaminant plumes. In archeology it is used for mapping of excavation sites prior to disrupting and digging. Ground Penetrating Radar can reveal near-surface structure in bedrock and soils.

Describe how ground penetrating radar (GPR) works.

Ground penetrating radar uses radar pulses to imagine the subsurface. It is a non-destructive method utilizing electromagnetic radiation in the microwave band. Reflected signals reveal subsurface detail. GPR uses transmitting and receiving antennas that radiate short pulses of the high-frequency radio waves into the gorund. When the wave encounters a buried object or a boundary with different properties, the receiving antennae receives variations in the relfected return signal. These variations in the return signal are converted into a real-time image displayed on an on-site cathode-ray-tube type television screen. The technique is similar to refelction seismology, but electromagnetic energy is used instead of acoustic energy. The depth range is limited by electrical conductivity of the ground or the presence of other interference causing factors.

Review some of the natural and human-based sources of ground water pollution

Groundwater pollution may be attributable to natural as well as anthropogenic (human-caused) sources. Water quality of aquifers is affected by the geology from which the groundwater is abstracted. Groundwater pollution caused by man includes: industrial discharge of chemical wastes; discharge of inadequately treated human waste; surface runoff containing fertilizers, pesticides, and spilled petroleum products; underground fuel storage tank leakage; and surface runoff from construction sites or other impervious areas such as parking lots. Many chemicals undergo reactive decay or chemically change especially over long periods of time in groundwater reservoirs. A noteworthy class of such chemicals are the chlorinated hydrocarbons such as trichloroethylene, used in industrial metal degreasing, and tetrachloroethylene, used in the dry cleaning industry. Both of these chemicals, which are carcinogens themselves, undergo partial decomposition reactions, leading to new hazardous chemicals.

Describe some of the uses of grout, and how it should be mixed correctly

Grout is a mixture of cement and fine sand that is commonly forced or pumped into boreholes to prevent ground water seepage from flowing into an excavation or underground working. Grouting is utilized to seal crevices in a dam foundation, or to consolidate and cement together rock fragments in a brecciated or fragmented formation. Grout is often used to stabilize abandoned mine related subsidence hazards in areas of near-surface mining. Pressure grouting is used to re-densify vuggy ground and to re-level structures damaged by subsidence or settling. Grout is typically prepared with very high slumps and most often does not contain a coarse aggregate faction. It is usually a combination of cement, sand, fly ash, and water. Some grout is prepared so as to be non shrinking in order to insure competent seals

Describe these terms relating water's potential energy to its pressure and height: head, potentiometric surface, hydraulic gradient

Head, or hydrostatic head, is defined as the pressure exerted at any given point in a body of water at rest. The hydrostatic pressure of ground water is generally due to the weight of water at higher levels in the zone of saturation. A potentiometric surface is an imaginary surface representing the total head of ground water. It is defined by the level to which water will rise in a well. The water table is a particular potentiometric surface. Hydraulic gradient is the difference in potential energy between two points on the body of water, divided by the horizontal distance between the two points. The hydraulic gradient describes and quantifies the slope of the water table or potentiometric surface.

Explain how High Altitude Color Infrared images are collected, and discuss what sorts of geologic analyses can use them.

High-altitude color infrared images are taken by aircraft flying at extremely high altitudes. The camera used to take these photographs typically have special filters to block out blue and ultraviolet wavelengths, so that the images will only use the red, near infrared, and infrared portion of the electromagnetic spectrum. Infrared radiation has a longer wavelength than visible light, and when combined with near infrared portion of the visible spectrum, is very effective in thermal mapping. Objects that reflect near infrared wavelengths well will appear red on the photographs, and other objects that do not refect infrared radiation as well will appear green. This kind of photography is used in both military and civilian applications for determining heat spectrums on the ground. Its uses in geology include mapping of volcanic features and near-surface plutonic activity. False color infrared images are useful in assessing content of moisture in the soil.

Describe hydraulic conductivity, including what factors it depends on and how it is caluclated

Hydraulic conductivity is defined as that property of soil or rock that determines the relative ease or difficulty with which a fluid, typically water, can be transported through that medium. It is dependent upon the intrinsic permeability of the material and on the degree of saturation of that material. Hydraulic conductivity is the proportionality constant in Darcy's Law. Hydraulic conductivity can be calculated with the following equation: K = ki * y/u where K is the hydrualic conductivity, ki is the intrinsic permeability of the medium, y is specific weight, and u is the dynamic viscosity. As the number of fractures or voids in a material increases, so do the values for intrinsic permeability and hydraulic conductivity. Geologists evaluate hydraulic conductivity values with pumping tests, computer models, and laboratory simulated flow tests. Hydraulic conductivity is a logarithm, so the values are expressed in orders of magnitude rather than on a linear scale.

Provide examples of depositional traps for petroleum

Hydrocarbon traps include both structural and stratigraphic traps. Structural traps are formed when sedimentary strata are deformed by folding, faulting, or diapirism, creating an impediment to upward oil migration. Anticlines are very effective hydrocarbon traps as they produce downward flexing pockets in packages of sediments in which oil can accumulate. Salt dome diapirism is the vertical emplacement of plastic salt bodies upward into higher stratigraphic sections of strata. The impervious nature of these salt bodies creates an aquitard within the sediments they have pierced, facilitating the trapping of mobile hydrocarbons. Faulting can bring impermeable strata against reservoir rocks, trapping hydrocarbon against the fault. Stratigraphic depositional traps are created when relatively impermeable strata, such as shales or mudstones, occur either horizontally (facies change) or vertically adjacent to reservoir rocks. Hydrocarbon migrating horizontally or vertically will become trapped as impermeable strata (aquitards) are encountered

Explain where petroleum deposits are found

Hydrocarbons are less dense than rock or water causing them to migrate upward through adjacent rock layers until they either reach the surface or become trapped beneath impermeable rocks. Because of this fact, petroleum deposits are generally found associated with large packages of sedimentary rocks. Anywherre sedimentary rocks occur is a potential source of petroleum. This includes the thick sequences of continental sedimentary rocks known from numerous areas around the globe. Offshore deltaic and continental shelf sediments are also a strong location for petroleum discovery. Hydrocarbons are typically found in traps within large sedimentary packages. Traps include both structural and stratigraphic traps. Structural traps can be very effective in concentrating hydrocarbons over a large area. Important structural traps include domes, anticlines, and folds. Fault related features also act as structural traps. Stratigraphic traps are formed when impermeable barriers or beds seal a reservoir bed or when permeability changes within the reservoid strata itself.

Provide an overview of the proccesses that form petroleum traps, and review the resulting characteristics of the traps

Hydrocarbons migrate upward through adjacent rock layers until they either reach the surface or become trapped beneath impermeable rocks. This process occurs because hydrocarbons are less dense than rock or water, forming accumulations called reservoirs. This process is not simple as it is influenced by underground water flows and by the structure of confining rocks. Typically, oil may migrate hundreds of kilometeres horizontally, vertically, or even short distances downward before becoming trapped in a reservoir

Discuss the stratigraphic ways to identify faults on a map, even if faults are not marked

Identification of faulting on a geologic map is easily accomplished by observing disruption in normal sedimentary outcrop patterns or sections. Even when faults are not marked on the map, it is possible to identify sedimentary outcrop pattern irregularities. Sedimentary rock units typically produce unbroken polygons on a geologic map, unless they are severely folded. Sedimentary units or groups of units which truncate against each other are a major fault indicator. Conversely, thickening of sedimentary units that cannot be attributable to folding is indicative of faulting. If two beds lie on opposite sides of a fault and have moved along either the strike or dip of the fault, they may either repeat or be absent after erosion. If the strike of the sedimentary beds is cut in a perpendicular fashion by a fault, there will be discontinuities as a result of the offset.

Explain how well efficiency can be estimated from a distance-drawdown graph.

If it is assumed that the entire vertical extent of an aquifer has been screened, it is possible to use a distance-drawdown graph to estimate well efficiency. The screen should be made of some material that allows the water from the aquifer to flow into the borehole, while still preventing the well from collapsing. Well efficiency can be calculated on the distance-drawdown graph by extrapolating the line backwards towards the pumping well. It is essential that the borehole not contain any elements that will interfere with the slow suction of water from the well. In the best case scenario, wells can only provide about 80% efficiency. A more rigorous method of evaluating well efficiency involves comparing the functional relationships between the actual discharge drawdown curve versus the curve produced by a properly developed well.

Discuss how igneous rocks are classified

Igneous rocks are rocks that are formed from cooling magma or lava. They can be classified in any of several different ways, including mode of occurrence, texture, mineralogy, and geometry. Mode of occurrence is the most common. Igneous rocks are classified by mode of occurrence as intrusive (plutonic), extrusive (volcanic), or hypabyssal. Intrusive rocks are coarse grained rocks that are formed by slowly cooling magma far below the earth's surface. Extrusive rocks are smooth and fine-grained rocks that are formed by faster cooling magma at or above the earth's surface. Hypabyssal rocks are less common rocks that are formed only slightly below the earth's surface. In terms of texture, igneous rocks are classified as either phaneritic or aphanitic. The phanerites are igneous rocks in which crystal structure can be identified megascopically (by the naked eye). Fine-grained igneous rocks in which mineralogy cannot be determined megascopically are classified as aphanites. In general, phanerites are intrusive rocks, while aphanites are extrusive rocks.

Discuss the formation of weathering deposits, and provide some examples

Important ore depostis associated with the weathering of rocks include aluminum/bauxite deposits, oxide deposits, and supergene enrichment of precious/base metal deposits. Weathering of aluminum-rich bedrocks, such as granite, gneiss, basalt, syenite, and shale in tropical lateritic environments produces important ore deposits of aluminum. The predominant minerals in bauxite deposits are gibbsite, boehmite, and diaspore. Weathering produces some economically importatn oxide deposits including conversion of primary magnetite minerals into secondary hematite. These accumulations of secondary hematite gravels are referred to as pisolites. Supergene enrichment invovles the in situ concentration of precious/base metal deposits in the near surface zone of weathering. In the supergene zone of an ore deposit, weathering will cause the formation of complex oxide minerals that are frequently very much enriched in the target metals of the deposit.

Discuss how storativity, or storage coefficient, is calculated for a confined aquifer

In a combined aquifer, there is a more complex interplay between the potentiometric surface, water release, and hydrostatic head. Even if the release of water from a confined aquifer lowers the head, the aquifer will remain saturated if the potentiometric surface remains above the aquifer. When water evacuates a confined aquifer the pressure within the aquifer descreases and the remaining water expands. The storage coefficient, or storativity, of a confined aquifer is calculated with the following equation: S = b * Ss where S is the storativity, b is the saturated thickness of the aqufier, and Ss is the specific storage, or the amount of water per unit volume of the aquifer that is lost or gained due to compressibility. Storativity values for a confined aquifer range between 0.001 and 0.00001.

Review the trigonometric relationships between an acute angle of a right triangle (a) and its neighboring sides (adjacent, opposite, hypotenuse)

In a right triangle, the relationship between the lengths of the sides can be determined with the trigonometric functions sine, cosine, and tangent, if the value of the two acute angles can be determined. By selecting and knowing the value in degrees of one of the acute angles, and the length of one of the sides, the lengths of any of the other sides can be determined. The since of the known angle is equal to a ratio of the length of the opposite leg of the triangle divided by the length of the hypotenuse of the triangle. The cosine of the known angle is equal to a ratio of the length of the adjacent leg of the triangle divided by the length of the hypotenuse. The tangent of the known angle is equal to a ratio of the length of the opposite leg divided by the length of the adjacent leg of the triangle.

Explain how to apply the TEGD guidelines for sampling and analysis of a monitoring well

In accordance with the TEGD mandates for the sampling and analysis of monitoring wells, a record must be kept of the methods of sample collection, analysis, preservation, shipment, chain of custody, and quality control. The static water level must be measured to within 0.01 feet before a water sample is collected. Before and after collection, the temperature, specific conductance, and pH of the well should be measured. Any contaminating materials that lie atop the water column should be recorded. If there are any contaminants on top of the water column, the well should be evacuated between one and three times. At no time should the sample be shaken. Sample blanks, standards, lab blanks, spiked sampled, and duplicated can be used to maintain quality control.

Describe the three types of strain that material can experience based on different types of shear

In any branch of science dealing with materials and their behavior, strain is the geometrical expression of deformation caused by the action of stress on a physical body. When an object is subjected to pure shear stress, this is known as volumetric strain. Volumetric strain is quanitified as the ratio of the change in volume to the original volume. Shear strain, on the other hand, is the result of either simple or simple rotational shear. Shear strain is calculated as the maximum displacement divided by either the tangent of the angle of displacement or the link between the bottom and top planes of the object. Axial strain, otherwise known as normal strain, is a compressive force that acts along one axis of the object. It is calculated as the ratio of the change in length divided by original length.

Review some of the techniques used when grouting dams

In dam construction, grout can be used to prevent seepage and to enhance stability of the overall dam. It should be applied after the site has been excavated but before dam construction begins. Often times, engineers will use so called grout blankets, which are broad expanses of relatively thin grout, in order to limit permeability on the upstream side of the dam. In order to increase the strength of surrounding rocks, engineers might use off pattern grouting techniques, which involve forcing grout into specially arrayed boreholes

Discuss how cement aggregates must be engineeres to gain the maximum strength and longevity

In its simplest form, concrete is a mixture of paste and aggregates. The paste is composed of portland cement and water and acts to coat the surface of both the fine and coarse aggregates. Through the chemical reaction known as hydration the paste hardens and gains strength to form a rock like mass called concrete. Typically, a mix is about 10 to 15 percent cement, 60 to 75 percent aggregate and 15 to 20 percent water. Entrained air in many concrete mixes may also take up another 5 to 8 percent. It is a good rule of thumb to keep water as minimal as possible. As for the aggregates, they should be chosen with an eye towards size and grade. Materials that are likely to become corrupted during multiple freeze and thaw sessions should be avoided. The following materials should never be used in a cement aggregate: coal, alkali, mica, or clay

Explain the mathematical methods for calculating both strike and dip

In order to calculate strike, one must contrast elevations with the distances between points. Also, one must be well versed in right angle trigonometry. First, locate a point, expressed here as X, on the line in between the highest and lowest points, A and C, respectively. X should have the same elevation of the middle point B. Then, the equation can be: (B -C)/(A-C)= (CX)/(CA), or (mid point elevation - low point elevation)/(high point elevation - low point elevation) = (distance from low point to point X)/(distance from low point to high point). The answer is the measure of the distance from C to X along the line CA. The line that runs between X and B is the strike. In order to determine dip, the following equation can be used: Tan(angle) = rise/run

Review the four categories of depth problems

In order to solve a depth problem, you must be provided with a point, strike, scale, and north heading. The easiest method of solving a depth problem is by constructing a geologic map projection utilizing trigonometry. There are four basic categories of depth problem: - horizontal ground surface, distance from surface to where depth has been measured is perpendicular to strike along dip direction - horizontal ground surface, distance from surface to where depth is measured not perpendicular to strike along dip direction - sloped ground surface, transverse from outcrop to location of depth measurement is not perpendicular to strike - sloped ground surface, transverse from outcrop to location of depth measurement is perpendicular to strike along dip direction

Discuss how wells are numbered in square plots using the standard system based on the Public Land Survery

In the Public Land Survey all areas are divided by the Township and Range system, based off a meridian or reference baseline. Each square township has a width of 6 miles, and is further subdivided into 36, 1 square mile sections. The PLS Township numbering system is such that Townships are numbered from north to south away from a meridian. Ranges are numbered east to west on either side of E-W meridians. Sections within a township are numbered, 1 through 36, in a contiguous, descending pattern, beginning at the upper right corner of the township. Each sections is further divided into 16 parcels of 40 acres each. These parcels are referred to as quarter-quarter (1/4 1/4) sections. These parcels are given letters A through R (I and O are skipped). When more than one well is drilled in a parcel, the designation of the well will include a number.

Discuss how organic soils and boundary soils are classified in the Unified Soil Classification System (USCS)

In the Unified Soil Classification System (USCS), highly organic soils are labeled Pt (peat). There are organic subdivisions in the silt and clay divisions, both those wiht high and low liquid limit. Organic soils are those that have an organic content above 18%. If the organic content is between 18 and 36%, the soil is most likely an organic clay or an organic silt. If the sample has an organic content between 36% and 90%, it is classified either as peaty. A boundary soil is one that has characteristics of two different soil types. Boundary soils will typically have a liquid limit value close to 50 so that they straddle the dividing line between the two subdivisions of silt and clay

Define the following terms related to the spreading of dissolved materials in groundwater: infiltration, retardation, diffusion, dispersion, advection

Infiltration is the flow of a fluid into a solid substance through pores or small openings. In groundwater issues it is the movement of water into soil or porous rock. Retardation refers to any effect or remediation technique that is aimed at slowing down or stopping the dispersion of ground water contaminates. Diffusion is the net movement of particles or dissolved materials from an area of high concentration to an area of low concentration. Molecules will diffuse in a random fashion between areas of high and low concentration. As time progresses, the gradient will grow increasingly shallow until the concentrations are equalized. Dispersion is the fairly permanent suspension of finely divided but undissolved particles in a fluid. Advection is transport in a fluid. The fluid is described mathematically for such processes as a vector field, and the material transported is described as a scalar concentration of substance, which is present in the fluid

Describe how to remove water hardness

It is possible to remove hardness from water. Temporary hardness can be removed from a water by boiling it which causes the calcium and magnesium to precipitate out of the solution as bicarbonate or carbonate. However, a certain amount of calcium and magnesium will remain in the solution. These ions, along with other iron and manganese ions, constitute non-carbonate hardness. Methods to reduce the hardness of water include distillation, use of a reverse osmosis system, or the use of water softeners. Water softeners utilize a technique called ion exchange in which calcium and magnesium ions are exchanged for sodium ions. Commercially, hard water problems are addressed through the addition of chemicals and by large-scale softening with zeolite and other ion exchange resins.

Desribe how the Rule of V's can be used to interpret a map that does not include topography

It is possible to use the Rule of V's to interpret a geologic map that does not include topography by examining the V shaped outcrop pattern of geologic units that directly cross stream valleys. The general rule is the wider the V, the steeper the dip of the bed crossing a valley. If the V shaped outcrop of a geologic unit points downstream, the dip of the bed must be greater than the gradient of the valley. If the V is wide, open, and points upstream, it indicated that the dip of the formation is upstream and steep. If the V is particularly narrow, the bed is probably close to horizontal or nearly flat lying. Completely horizontal bedding will not produce V shaped outcropping at all. The outcrop pattern produced by a unit with vertical bedding will be straight lines across the topography of the valley.

Describe the topography of a karst region and discuss the conditions necessary to develop such a region. Provide examples of karst regions in the United States.

Karst topography is a landscape that has been shaped by the dissolution of a soluble layer or layers of bedrock, usually carbonate rock such as limestone or dolomite. These landscapes display distinctive surface features and underground drainage, and in some examples there may be little or no surface drainage. Some areas of karst topography, such as southern Missouri and northern Arkansas in the United States, are underlain by thousands of caves. Karst landforms are caused by mildly acidic groundwater exposed to soluble bedrock. Carbonic acid causing these features is formed by atmospheric carbon dioxide dissolves in the water. In the United States, karst regions occur in every state. The largest are in central Florida, south central Indiana, and southwestern Mississippi.

Review the main types of dams that are built in the United States.

Large dam in the USA are typically mansory arch dams. In the arch dam, stability is obtained by a combination of arch shape and gravity action. The large dams such as Hoover Dam are concrete gravity arch dams. Gravity dams are desinged to ensure that their stabilities are secured by size and shape. This guarantees that they will resist overturning, sliding and crushing at the toe. Embankment dams are made from compacted earth, and have three main types, rock fill, earth fill, and asphalt concrete core dams. Embankment dams rely on thier weight to hold back the force of water. A cofferdam is commonly made of wood, concrete, or steel sheeting, and is a (usually temporary) barrier constructed to exclude water from an area that is normally submerged.

Explain how magmatic segragation deposits form, and discuss their categories

Magmatic deposits are related genetically with magmas that are emplaced into the crust. These deposits occur within the lithologies derived from the crystallization of such magmas. The most economically importatn magmatic depostis are related to mafic and ultramafic melts. These important deposit types include chromite deposits, nickel-copper deposits, and platinum group metal (PGM) deposits. Chromite deposits form as the product of the separation of the earliest crystallized solid phases, including chromium-rich spinels, which settle out from a differentiating melt. Chromite deposits can be either stratiform or podiform in habit. Nickel-copper deposits form as the end member of a process known as liquid immiscibility. This process involves the separation of a sulfur-rich liquid, containing Fe-Ni-Cu, from a parental magam. The sulfur rich liquid produces an immiscible sulfide phase that segregates and settles to the base of the intrusive body. PGM deposits are similar in formation to nickel copper segregation deposits.

Describe how a magnetic survey is performed, and what kinds of data it can provide.

Magnetic surveys and prospecting are now carried on predominantly with airborne instruments. Magnetic surveys maps variations in the magnetic field of the Earth that are attributable to changes of structure or magnetic susceptibility in certain near-surface rocks. Sedimentary rocks generally have a very small susceptibility compared with igneous or metamorphic rocks, and most magnetic surveys are designed to map structure on or within the basement, or to detect magnetic minerals directly. Magnetic surveys are performed with a geophysical instrument similar to the gravimeter in that absolute magnetic values are not measured, but only the differences in vertical magnetic force between field stations and a selected base station. Magnetic surveys can provide information of subsurface structure of bedrock and location of magnetic lithologies.

Explain the different ways that map scale may be indicated

Map scale will be indicated in one of two ways: either with a bar scale or a ratio. A bar scale is typically a graduated line placed near the bottom center of a map that displays distances on the actual map. Bar scales usually show miles and kilometers and allow the map user to directly measure distances on the map by observing the number of defined graudations (miles, kilometers, feet) between desired points on the map. A ratio scale is somewhat more difficult to use than a bar scale. The ratio used for map scaled is always in the form of 1:X. In a ratio scale the numerals do not refer to any specific unit or length of measure. Accordingly, the map scale of 1:5,000 can be interpreted as "one unit on the map is equal to 5,000 units on the ground" or "one inch on the map equals 5,000 inches on the ground"

Discuss how metamorphic rocks are classified

Metamorphic rocks are classified genetically by their environment of metamorphism. The three major sub classes are: rocks produced in response to dislocation metamorphism, rocks fromed in contact zones around igneous intrusions, and rocks metamorphosed regionally during mountain building episodes. Cataclasites are formed as a result of mechanical breakage and distortions that occur during crustal movements. Cataclasites can be formed from any rock and consist of any mineral assemblage. Contactites form when hot magme is intruded into relatively cooler host rocks, heating and metamorphosing the surrounding country rock. Changes can range from complete recrystallization to minor color changes. Regional metamorphic rocks consist of extensive volumes of rock that undergo textural and compositional changes in response to mountain building. Regional metmorphism involves recrystallization and new mineral growth under increased pressure and temperature.

Disucss the ways in which ore deposits are classified based on their genesis, including mineral and chemical compositions

Mineral deposits are classified in a number of different ways. The msot basic classification system utilizes mineralogy. In this system the economic minerals contained in the deposit are designated, such as: massive sulfide, lead/zinc, or gold/silver deposit. This method does not designate mode of formation, temperature, or field habit. Mineral deposits are often classified by thier temperatures of formation. These deisgnations, epithermal, mesothermal, and hypothermal, refer to low-temperature, medium-temperature, and high-temperature respectively, and are useful as certain minerals or groups of minerals are recognizable by their temperature environment. The most common classification system utilizes mineralogy and field habit. In this system, the field habit of the deposit is modified by listing the minerals of the deposit such as: narrow vein gold/silver, lead/silver replacement, or disseminated gold/sulfide

Explain how deposits are anticipated to form from solution-remobilization

Mineral deposits related to solution and remobilization are called hydrothermal ore deposits. Cells of thermally heated groundwater near igneous intrustions, and in other areas of increased thermal gradients, circulate convectively dissolving metallic elements from country rocks. These metal laden hydrothermal fluids rise upward or outward from source and fill fractures and weak zones in the rocks above. When temperature decreases sufficiently, or chmeical conditions change due to interaction with wall rocks, dissolved metals in these fluids will precipitate out forming metallic veins or replacement deposits. Hydrothermal deposits are divided into the following classifications based on temperature of formation: epithermal (50 to 200 degrees C), mesothermal (200 to 300 C) and hypothermal (300 to 500 C). Different mineral assemblages are associated with each temperature range and hence, the presence of deisred mineral species can be anticipated if the mineralogy and field characterisitcs of the occurence can be classified.

List mining methods used to extract resources of interest for economic geology.

Mining methods are directly related to ore body configuration, ore grade, structure of host rocks, and economics. The mining method is designed to maximize recovery of ore and safety. Many ore bodies are amenable to surface mining and will be mined through the use of open pit mining. Open pit mining is perhaps the least expensive mining method and allows for the mining of large high tonnage, low grade deposits. Underground mining mehtods consists of: drift mining, slope mining, shaft mining, drift and fill, sublevel caving, block caving, shrinkage stoping, longwall mining, room and pillar, and retreat mining. In situ mining, also known as solution mining, involves the pumping of reactive fluids from the surface down into a mienral deposit to dissolve the desired constituent. The mineral laden fluid is then recovered and the desired commodity is recovered from the pregnant solution.

If you were looking at a geologic map, you would see a map scale, north arrow, magnetic declination, and explanation, topographic symbols, and geologic symbols. Explain what information each of these items provides

Most geologic maps give a magnetic declination, which indicates the difference in degrees between true geographic north and magnetic north for the area covered in the map at the time the map was published. Magnetic declination changes over time. Most geologic maps are true geographic north oriented such that the presented north arrow on the map points to the top of the map indication no need to rotate to achieve true geographic north orientation. This is not universally true as north may be presented at any orientation around a 360 degree circle. The map distance on a map relative to the distance on the ground. Most maps will contain a key or legend, describing all the symbols and units used on the map. Also, topographic maps will indicate the basic geomorphic features of the region. The geologic map symbols are used to indicate fold, lithology, thickness, bedding, fault, cleavage, foliation, and information about joints. The map key for a given map usually only contains the symbols that appear on that map.

Define the following types of very commonly encountered faults: normal fault, reverse fault, strike-slip fault.

Normal faults, reverse faults, and strike-slip faults typically range from 45-90 degrees of dip. Fault orientation and relative movement are described in terms of the two surfaces involved, the footwall and the upper hanging wall. In a normal fault, the hanging wall will move downward in relation to the footwall. Normal faults characterize extensional tectonic environments in many instances. A reverse fault is opposite from a normal fault in that the upper hanging wall is displaced upward past the footwall. Reverse faults suggest compressional tectonic regimes. In a strike-slip fault the movement is parallel to the strike of the fault plane with no relative up or down displacement of headwall or footwall. From an elevated vantage point, a normal or reverse fault will have appeared to have moved up or down, whereas the strike-slip fault will appear to move from side to side.

Describe the geological age-dating techniques based on biological or evolutionary evidence.

Oftentimes geologists will use paleontology and evolutionary theory to date geological units. This type of age dating is referred to as relative age dating becuase the age of the material in question is assigned a bracketed age instead of an absolute number. The fossil assemblage existing within a rock specimen can be used to determine an upper and lower possible age of the material based on the known or suspected histories of these animals and/or plants preserved as fossils. As many plant and animal species display a known progression of morphological development or transportation into sub-species through time, a relative age for the material which hosts their remains or impressions of their remains can be determined. Frequently, the relative age can be narrowed down by looking at a number of fossils within a sample and cross referencing with known material nearby that may have been radiometrically dated.

Provide the equation used to calculate the recoverable stock tank oil (STO) reserve in cubic feet, and discuss how it is applied

Oil in place is the total hydrocarbon content of an oil reservoir and is often abbreviated STO. Oil in place is a different term from oil reserves. Geologists use the recoverable stock tank oil (STO) reserve equation to calculate the amount of oil that can be recovered from a reservoir with existing technology. The amount of oil that can be recovered will depend on the viscosity, the permeability of the reservoir, the production system, and the ratio of gas to oil. The equation is as follows: N = CVb*phi(1-Sw)R/FVF where N is the stock tank oil in place, Vb is the bulk rock volume, C is a constant that depends on the units used for volume, phi is the fluid filled portion of porosity, Sw is the water saturation, R is the percentage of oil that is recoverable, and FVF is the formation volume factor

Explain how plunge of a fold can be determined using strike and dip, and how closure can be shown in an outcrop so that folded map units can be interpreted.

On a geologic map a plunging fold will generally produce a U shaped outcrop pattern. If the fold is symmetrical, the fold axis line will evenly bisect this U shaped outcrop and will be offset if the fold is asymmetrical. Strike and dip (attitude) symbols on the limbs of the fold will also trace a U shaped pattern on the map outcrop pattern. The plunge angle of the fold is determined by the value of dip for attitude symbols occurring closest to the fold axis line. Plunging folds are said to be closed folds due to the U shaped outcrop pattern produced. A plunging anticline dips towards the closure in the U shaped outcrop pattern, whereas a plunging syncline will dip away from the closure in the U shaped outcrop pattern. The youngest components of a syncline will lie along the fold axis, whereas the oldest units of the anticline will lie along the fold axis.

Describe the geologic map symbols used for faults and folds

On geologic maps faults are indicated by solid, dashed, or dotted lines with various symbols used to indicate relative displacement. exposed faults between rock units are shown as a solid line tracing fault across topography. Dashed lines indicate approximate or inferred location, and dotted lines depict faults that are covered by surficial deposits or concealed. Displacement of a high angle fault is indicated by a bar and ball on downthrown side. Fault dip, if known, is indicated as a numeral next to bar and ball. Thrust fautls are shown as solid, dashed, or dotted lines and the upper plate is marked with black triangular teeth. Fold axes are traced with similar rules pertaining to faults: solid where exposed, dashed where inferred, and dotted where concealed. Smaller arrows are placed perpendicular to fold axis and radiate outward for an anticline and inward for a syncline. Fold depiction on a geologic map is facilitated by strike and dip symbols working together with the fold axis line. From these sets of symbols, a mental picture of structure emerges.

Describe the distance-drawdown method of analyzing aquifer drawdown tests

One variation of the Jacob straight-line method is called the distance-drawdown method. This technique is used to consider data from three or more observation wells. The drawdown is plotted versus distance from the drawdown well on the linear side of semi-log paper, and the linear portion of the data from the closest wells is extrapolated backwards to zero-drawdown axis. The following equations are used to determine the characteristics of the aquifer: T = 35Q/ds S = Tt0/640r^2 where T is transmissivity, Q is pumping rate, ds is the change in drawdown (over one log cycle from the plot), S is storativity, t0 is the time at the zero-drawdown point from the plot, and r is the distance between the pumping and observation wells.

Explain the difference between light and dense non-aqueous phase liquids, and how their characteristics affect remediation

Organic contaminants are either described as light non aqueous phase liquids (LNAPLs), or dense non aqueous phase liquids (DNAPLs). The designations depend upon whether their density is greater or less than that of pure water. The density of pure water is established at 1 g/cm^-3. LNAPLs mainly originate in petroleum products, and are soluble in water. These liquids can only be cleaned up through venting, bioremediation, excavation, and barrier construction. DNAPLs, on the other hand, include coal tar, chlorinated solvents, and creosote. These liquids are slightly soluble in water, and tend to accumulate at the bottom of aquifers. Cleanup of DNAPLs includes biodegradation, physical barrier construction, or pumping. Both LNAPLs and DNAPLs are characterized by their solubility, vapor pressure, viscosity, and wettability.

Discuss the three phases of matter found in partially saturated soils and how they contribute to volume and weight relationships

Partially saturated soils will contain matter in the solid, gas, and liquid phases. The volume of a partially saturated soil can be calculated with the equation: V = Va+Vw+Vs, in which Va is the volume of air, Vw is the volume of water, and Vs is the volume of solids. When soil water content is reduced below saturation the interface between air and water within pores are curved because of surface tension. As the water content is reduced, drainage occurs from progressively smaller openings, and the interface radius decreases. On occasion, it will be necessary to simply calculate the volume of air and water, which is expressed as Vw. It can be assumed that the gaseous constituents of a partially saturated soil do not have any weight

Compare and contrast the Unified Soil Classification System (USCS) and the Modified Wentworth (MW) scale

Particle size, also called grain size, refers to the diameter of individual grains of sediment, or the particles in clastic rocks. There are two different scales used to classify the grain size of soils: the Unified Soil Classification System (USCS), and the Modified Wentworth (MW) scale. The USCS scale is typically used for soils, while the MW scale is more commonly used for rocks. In the Modified Wentworth scale size ranges define limits of classes that are given names. The classes: coarse, medium, and fine, are augmented by the qualifying term "very" for further distinction. The use of this scale relies on observation, rather than the sieve analysis used in the USCS scale. The USCS system relies more on specifications based on sieve analyses. The classification system can be applied to most soils and unconsolidated materials, and is represented by a two letter symbol

List some of the most common organic contaminants appearing in water, and discuss their sources and effects.

Persistent organic pollutants (POP's) appearing in surface water and groundwater, some that can be resistant to biodegradation, are an environmental threat due to long-range transport, bioaccumulation in humans and animals, and biomagnification in the food chain. Organic pollutants that are commonly at issue are aldrin, chlordance, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene, mirex, polychlorinated biphenyls (PCB's), polychlorinated dibenzofurans, and toxaphene. Many of these chemicals are characterized by low water solubilities, high lipid solubilities, semi-volatility, and high molecular mass. One important factor of their chemical properties that is problematic arises from their ability to pass through biological membranes and accumulating in the fatty tissues of living organisms. These compounds originate from numerous industrial and agricultural sources as primary and secondary pollution.

Describe the most common pesticide contaminants found in ground water, and discuss their effects on human health

Pesticides can be classified as synthetic pesticides or biological pesticides, although the distinction can sometimes blur. There are three major routes through which pesticides can reach a groundwater aquifer: it may percolate, or leach, through the soil, it may be carried to the water as runoff, or it may be spilled, for example accidentally or through neglect. The most common pesticide contaminants found in groundwater are as follows: DDT, DDE, DDD, chlordane, aldrin, and dieldrin. DDT, when it decomposes, becomes DDE and DDD. Aldrin and dieldrin adhere to the particles of soil, and frequently leach into aquifers. For human beings, the greatest risk associated with pesticides has to do with eating food that has become contaminated with one or more of these compounds. Consumption and assimilation of pesticides by humans can result in damage to the nervous system, reproductive system, and can be carcinogenic.

Disucss the components of petroleum and its uses.

Petroleum, or crude oil, is a naturally occurring liquid found in formations in the Earth consisting of a complex mixture of hydrocarbons (mostly alkanes) of various lengths. The approximate length range is C5H12 to C18H38. Any shorter hydrocarbons are considered natural gas or natural gas liquids. In its naturally occurring form petroleum contains other nonmetallic elements such as sulfur, oxygen, and nitrogen. It is usually black or dark brown (although it may be yellowish or even greenish) but varies greatly in appearance, depending on its composition. Petroleum is composed of long chain and short chain hydrocarbons. Petroleum is turned into the following fules: ethane, diesel, fuel oil, gasoline, jet fuel, kerosene, liquid petroleum gas (LPG), and natural gas. Derivative products of petroleum include: alkenes, lubricants, wax, sulfuric acid, asphalt, and paraffin.

Describe how sodium buildup is quantitatively evaluated in soils

Plants are detrimentally affected, both physically and chemically, by excess salts in some soils and by high levels of exchangeable sodium in others. Soils containing accumulations of excahngeable sodium are typically of poor tilth and low permeability. These attributes render these soils unfavorable for plant growth. Simply measuring the level of sodium in a soil does not give an accurate picture of the effect of this sodium on the soil. This is because high levels of sodium in soil can be rendered more harmful and augmented by correspondingly high levels of calcium and magnesium. Soil scientists gauge the effects of sodium on the soil with the equation for sodium absorption ratio (SAR): SAR = Na/sqrt(Ca+Mg/2) where Na, Ca, and Mg represent the amount of sodium, calcium, and magnesium, respectively, in the soil. If the SAR value is lower than 10, the level of sodium in the soil is not considered to be very harmful.

Describe how porosity is calculated, and discuss the factors that affect porosity

Porosity is calculated with the following equation: n = Vv/Vt where n is the porosity, Vv is the volume of void space, and Vt is the total volume of the material (including the void space). A number of different types of porosity are recognized in geology. Primary porosity is the main or original porosity system in a rock or unconfined alluvial system. Primary porosity is a function of grain size, sorting, void spaces as a percentage of the whole, and hydrologic conductivity. Secondary porosity is a subsequent or separate porosity system and can add or subtract from primary porosity. Secondary porosity relates to chemical leaching of minerals or fracture system development. Secondary porosity includes fracture porosity and vuggy porosity, the latter formed when constituents such as fossils in rocks dissolve.

Distinguish between porosity and permeability, and describe how these differ from effective porosity and intrinsic permeability

Porosity, expressed as the letter n, is the percentage of a soil or rock that is occupied by pore space. The effective porosity (ne) is the proportion of the volume of a rock or soil that is comprised of interconnected pores through which fluid may flow. Effective porosity is the ratio of the volume of liquid that a given mass of saturated rock or soil will yield by gravity compared to the volume of that mass. Permeability, expressed with the letter k, is defined as the capacity for a rock or soil to transmit a fluid. Degree of permeability depends upon the size and shape of the pores, and the nature and extent of interconnections. It is measured by the rate at which a fluid of standard viscosity can move a given distance through a given interval of time. The unit of permeability is the Darcy. The intrinsic permeability (ki) of a rock or soil is the ease with which fluid flows through it at a specific hydraulic gradient.

Discuss the similarities and differences between quality assurance and quality control.

Quality assurance (QA) is the act of providing evidence needed to establish confidence that a task or analysis is being performed in the most effective manner. It refers to all planned and systematic actions necessary to provide a targeted level of confidence that a product or service will achieve or satisfy designated standards of quality. QA covers all activities from design, development, production, installation, and servicing to documentation. Quality control, on the other hand, is the system of ensuring that all the procedures involved in the performance of a project serve the goals of the customer. Quality control (QC) basically involves calibrating, fine tuning, and insuring the longevity of the processes that have been put into place by the quality assurance program. QA/QC are essential business management practices for all chemical sampling and chemical analysis operations to maintain confidence levels in complex data sets.

Explain how seismic refraction surveying examines subsurface materials

Refraction utilizes seismic waves traveling large horizontal and vertical distances along distinct interfaces in the Earth. Travel time required for these seismic waves gives information on the velocity and depth of certain subsurface formations. The detecting instruments are laid down at a distance from the shot hole that is large compared with the depth of the horizon to be mapped. The seismic waves may be generated with either a small explosion, a hammer, or a specially designed vibration truck. The basic conceptual understanding of the way that seismic waves move through layers of different density is known as Snell's law.

Compare the uses of seismic refraction, seismic reflection, and 3D seismic reflection or refraction

Refraction utilizes seismic waves traveling large horizontal distances along distinct interfaces in the Earth. Travel time required for these seismic waves gives information on the velocity and depth of certain subsurface formations. Seismic reflection maps the structure of subsurface formations by making use of the times required for a seismic wave to return to the surface after reflection from the formations themselves. The reflections are recorded by detecting instruments which are laid near the site of generation of the seismic pulse. Variations in reflection times can indicate structural features in the rocks below. Three Dimensional (3D) seismic is obtained through a set of closely-spaced seismic lines that provide a high spatially sampled test of subsruface reflectivity. The resultant data set can be observed in any direction without losing view characteristics of a well sampled seismic section. In a migrated 3D seismic data set all events are placed in their proper vertical and horizontal positions. This provides a much more detailed image than available with 2D seismic technique.

Review the temperature and pressure conditions that distinguish the specific categories of regional metamorphism

Regional metamorphism is classified according to temperature and pressure regimes: - Prehnite-pumpellyite facies: formed deep below water in sediment of greywacke, shale, and mafic rocks: zeolyte appears at a depth of 3000 to 15,000 feet, while pehnite-pumpellyite appears between 10,000 and 40,000 feet -blueschist or glaucophane schist facies: formed in subduction zones and other tectonically active environments; temperature between 300 and 400 degrees celsius, and pressure above 5000 bars -greenschist facies: form at slightly greater depth than blue schist; temperature between 300 and 500 degrees celsius, pressure between 3000 and 8000 bars - amphibolite facies: slightly deeper environment than greenschist facies; temperature is between 450 and 700 degrees celsius, pressure between 3000 and 8000 bars - granulite facies: formed in deep regional metamorphism; temperature above 650 degrees celsius, pressure between 3000 and 12,000 bars - eclogite facies: temperature between 350 and 753 degrees celsius, pressure above 7,500 bars

Review the two types of regional metamorphic deposits, and the products that are formed in them

Regional metamorphism occurs in areas of convergent plate tectonics. Subduction and continent-continent collision result in orogenesis and metamorphism. convergent boundary plate movements result in thrusting, folding, and faulting in the upper parts of the Earth's crust, and plastic folding, metamorphism, and plutonism (formation of magma chambers at depth) at greater depths. Metamorphism is the mineralogical, chemical, and structural adjustment of solid mineral assemblages to changing physical and chemical conditions. Metamorphism may occur due to increasing temperature, pressure, or both. Minerals of economic importance are associated with regional metamorphism. Some examples include: fine quality gemstone rubies (red corundum), from Burma (Myanmar), formed through the regional metamorphism of impure carbonate rocks. These pigeon blood rubies are the most valuable gemstones in the world. Most beryls, or emeralds and aquamarines, either crystallize from pegmatites (igneous processes) or through regional metamorphism of aluminous rocks to form talc and mica schists.

Contrast the effects of contact metamorphism, regional metamorphism, and cataclastic metamorphism on mapped lithologic units.

Regional metamorphism, depending on map scale, would most likely extend beyond map borders and would hence define an individual lithologic unit for that map. If the outward extent of regional metamorphism is captured on a geologic map, lithologic changes between metamorphosed and un-metamorphosed rocks would need to be deifned in the map key or accompanying report. As areas of contact metamorphism are usually localized around intrusive bodies, they are typically shown on a geologic map by a hachured pattern or area of shading. This can be addressed in the map report by describing mineralogic and textural changes to a lithologic formation affected by contact metamorphism in the hauchured area. Cataclastic metamorphism is defined as rock deformation accomplished by fracture and rotation of mineral grains or aggregates without chemical reconstitution. This type of metamorphism is associated with faulting, shear zones, and impact sites. Cataclasism can also be shown on a geologic map with hachuring or shading, similar to depiction of contact metamorphism, unless effects extend regionally necessitating a separate lithologic unit.

Distinguish between reserves and resources, and discuss the steps required to calculate reserves

Reserves are an estimate within specified accuracy limits of the valuable metal, hydrocarbon, or mineral content of known deposits that may be produced under current economic conditions and with present technology. Typically reserves are subdivided into three groups: proven, probable, and possible, all associated with a degree of confidence or upper limit of knowledge. Proven and probable reserves are essentially in hand. Possible reserves are yet to be defined and quantified. Resources, on the other hand, are all those known and unknown deposits, whether that can be extracted using existing technology or not. In order to calculate petroleum reserves, it is necessary to determine the volume of the reservoir rock as well as the degree to which this rock is filled with oil. Also, one must determine to what degree or efficiency the oil within the rock can be recovered.

Discuss how clastic rock types are classified, based on the particle and sediment types that create them.

Rock fragments and minerals that comprise detrital sediments are derived from pre-existing rocks that have undergone subaerial weathering and erosion. Detrital grains are then transported to be redeposited as sediment. Lithification or cementation produces a sedimentary rock. The predominatn detrital rocks are conglomerates, sedimentary breccias, sandstones, siltstones, and claystones. Conglomerates are made up of 50% or more rounded pebbles, cobbles, or boulders, whereas sedimentary breccias are made up of 50% or more angular pebble-, cobble-, or boulder-sized fragments. Sandstones consist of sandstone deposits that have been cemented or consolidated. Sandstones may be well laminated to thin- to thick- bedded. Quartz is the predominant material. Siltstones are silt deposits that have been lithified. Most siltstones occurr interbedded with sedimentary sequences that are predominately sandstone or shale. Claystones, mudstone, and shale are made up of clay-sized particles. Mudstones exhibit blocky cleavage as they contain more irregularily shaped particles than shales.

Explain why there can be repeated or missing rock units in a cross-section

Rock units can either repeat or be missing in a particular cross section due to bedding plane faulting, thrust faulting, or interruption by an unconformity. An unconformity in a sedimentary rock section is caused by periods of non-deposition caused by erosion due to exposure or uplift. Bedding plane faulting is often associated with regional low angle thrust or detachment structures. Thrust and detachment faults can break rock sections along bedding planes and transport these partial rock sections along with thrust plate movement. This can cause missing rock units where low angle faults or structures fractured along bedding planes. It is common in areas of thrust faulting for large sections or pieces of rock units to be stacked atop each other to produce a repeated section

Explain how salt water intrusion occurs and how it can be described mathematically

Salt water intrusion is a naturally occurring phenomenon in coastal aquifers. Because of the dissolved solute load, seawater has a higher density than fresh water. This higher density has the effect that the pressure beneath a column of saltwater is larger than that beneath a column of the same height of freshwater. If these columns were connected at the bottom, then the pressure difference would trigger a flow from the saltwater column to the freshwater column. Saltwater intrusion is limited to coastal areas. Inland the freshwater column gets higher and the pressure at the bottom also gets higher. This compensates for the higher density of the saltwater column and intrusion stops. The Ghyben-Herzberg ratio states, for every foot of fresh water in an unconfined aquifer above sea level, there will be forty feet of fresh water in the aquifer below sea level. The Ghyben-Herzberg ratio is calculated with the following equation: Z = 40 * ht where Z is the depth of the freshwater/saltwater interface below sea level, and ht is the height of the potentiometric surface above sea level.

Explain what sedimentary ores are, and describe how they are formed

Sedimentary ores occur when normal sedimentary rocks attain ore grade or are concentrated by normal processes. Some examples of sedimentary ore deposits include saline residues, phosphatic deposits, or bog iron ore of the Clinton type. Sedimentary ores are formed both by mechanical aggregation and through chemical precipitation operating syngenetically with the formation of the surrounding rock. The nature and tenor of sedimentary mineral deposits has changed throughout Earth's history in relation to changes in the oxidation (redox) state of the ocean atmosphere system and biological evolution. Mechanical accumulation or aggregation occurs when surficial geologic and geomorphic processes concentrate minerals by specific gravity or by size. Some of the most common types of mechanical accumulation deposits are alluvial placers are gold and platinum

Describe how to orient a bed vertically by interpreting physical wear evidence or biological features

Sedimentary rocks and packages of sedimentary rocks contain many structures that can be useful in re-orienting strata that have been disrupted from the original vertical position. Original depositional textures of individual beds, such as graded bedding, slump bedding, and lateral facies relationships can be recognized and used to re-orient strata. Post-depositional deformational characterisitics such as bioturbation (worm and insect burrows), ripples and ripple markings, sole markings, and other erosional and water-flow phenomenon are very useful in orientation of strata to their original positions. Asymmetrical bedding and depositional features related to wind, such as cross bedding, can be useful in reorienting out-of-place stratigraphic sequences. Entire packages of strata can also be re-oriented by an understanding of stratigraphic sequences operating in an area.

Discuss the frequency of various sedimentary rocks, and the processes that form sedimentary rocks. Provide an overview of the categorization of sedimentary rocks.

Sedimentary rocks may be deposited physically, chemically, or biologically. Although some chemically precipitated sedimentary rocks are formed as a solid aggregate, most sediments must be lithified by cementation to form a rock. Sedimentary rocks are divided into three main categories: detrital sedimentary rocks, consisting of loose rock and mineral fragments derived from erosion; chemical and biochemical rocks, made up of precipitated minerals; and diagenetic sedimentary rocks, formed as a result of recrystallization, replacement, or other chemical modification of the original sediments. Even though sedimentary and diagenetic rocks comprise less than 10% of the Earth's crust by volume, they cover some 75% of the continental surface. Ninety-five percent of all sedimentary rocks consists of sandstones, mudrocks, and carbonate rocks. Of these, the mudrocks are most abundant, making up about 65% of all sedimentary rocks. Sandstones make up 20 to 25% of all sedimentary rocks, and carbonate rocks account for about 10 to 15% of all carbonate rocks.

Discuss how seepage velocity differs from groundwater velocity

Seepage velocity is a parameter measured in soil mechanics more so than in groundwater studies. The seepage velocity of groundwater is the actual velocity with which groundwater moves through a porous medium. Groundwater is seldom discussed in terms of seepage velocity. Because no underground medium is perfect for fluid motion, seepage velocity is always lower than discharge velocity. Seepage velocity is calculated with the following equation: vs = Ki/ne where vs is the seepage velocity, K is the hydraulic conductivity, i is the hydraulic gradient, and ne is the effective porosity. Seepage is the flow of a fluid through pores. After measuring or estimating the intrinsic permeability (k), one can calculate the hydraulic conductivity (K) of a soil, and the rate of seepage can be estimated.

Discuss what shear strength of soils is, and how it can be measured and quantified

Shear strength describes the maximum physical ability of a soil to deform before a point of significant plastic deformation or yielding occurs due to an applied shear stress. Two theories are commonly used to estimate the shear strength of a soil depending on the rate of shearing as a frame of reference. The Tresca theory applies to short term loading and is also referred to as the undrained strength or the total stress condition. The Mohr Coulumb theory applies to long term loading of soil and is known as drained strength or the effective stress condition. In modern soil mechanics, including building design for earthquake protection, the above mentioned classical techniques are frequently superseded by critical state theory. The factors controlling shear strength in soils are: soil composition, state (or void ratio), structure, and loading conditions. Shear strength is determined and quanitified through the following tests: cone penetration test, direct shear test (ASTM D3080), triaxial shear test, and the unconfined compression test (ASTM D2166).

Discuss how Side-Looking Airborne Radar (SLAR) works and discuss its uses.

Side-looking airborne radar (SLAR) images are acquired by sending a beam of radar energy to the ground at an angle perpendicular to the aircraft's flight path. Unlike visible and near-infrared wavelengths, radar energy can penetrate most clouds, making it an especially useful tool where persistent clouds cover target areas. With SLAR the terrain is illuminated at an oblique angle to enhance subtle geologic structures such as folds and faults. Light and dark areas on the image are caused by high and low radar reflectivity, respectively. The size of objects discerned from SLAR depends upon the radar return, so the azimuth resolution of 10-15 meters is not necessarily a limiting factor. Side-looking airborne radar is used for terrain analysis in areas with frequent and dense cloud cover that restricts conventional camera-based imagery

Describe the seven types of silicate minerals, including examples and a discussion of their structures.

Silicate minerals are classified on the basis of the configuration of anions in the mineral structure. The shape of the silicate molecule is a tetrahedron with four large oxygen atoms surrounding a silicon atom. Silicate mineral construction is based on combinations of the silicate tetrahedron. There are seven basic types of silicate mineral: -Nesosilicates: contains SiO4; composed of an isolated tetrahedral; includes zircon, olivine, and garnet -Sorosilicates: contains Si2O7; isolated double or linked tetrahedral; includes lawsonite and hemimorphite -Cyclosilicates: contains SiO3; includes beryl group and tourmaline -Inosilicates (double chain): contains Si4O11; includes amphibole group -Phyllosilicates: contains Si2O5; forms sheets; includes biotite, talc, and chlorite -Tectosilicates: contains SiO2 and Si3O8; forms frameworks; includes feldspar and zeolite groups

Discuss the information that grain size and composition can provide for each type of clastic sedimentary rock: sandstone, conglomerate, and shale

Since most sedimentary rocks are derived by processes of weathering, transportation, deposition, and diagenesis, the textures we find in sediment and sedimentary rocks are dependent on the specific process and the order in which they occurred. These include: the nature of the parent rocks, the strength of the wind or water currents that carry and deposit the sediment, the distance transported or time involved in the transportation process, biological activity with the sediment prior to diagenesis, and the chemical environment under which diagenesis occurs. Grain sizes in conglomerate, sandstone, and shale are directly related to deposition energies of sediments which comprise these rocks. As the energy or velocity of transport decreases, heavier particles are deposited and lighter fragments continue to be transported. this results in sorting due to density.

State Snell's law, and discuss how it governs seismic refraction.

Snell's law describes the refraction of seismic waves through subsurface materials of varying density. The formula for Snell's law is as follows: v1/v2= sin(alpha)/sin(beta), in which v1 is the velocity through layer 1, v2 is the velocity through layer 2, alpha is the angle of incidence, and beta is the angle of refraction. If v2 is greater than v1, then the angle of refraction is greater than the angle of incidence. When seismic waves are sent into a two layer material, a portion of the waves will be reflected off the boundary between the layers, while another portion of the waves will be refracted at the next boundary between layers. The composition and weathering (if present) of the subsurface material will determine the velocity at which the refracted waves travel.

Relate the following quanitities, calculated in investigations of soil phase relationships: weight of solids, dry density, unit weight of dry soil, porosity and void ratio

Soil is usually composed of three phases: solid, liquid, and gas. Mechanical properties of soil directly depend on the way these phases interact with each other and with applies potentials. The following equations all have the same denominator and are used to calculate the above mentioned properties (w is the percentage of water content). The equation for the weight of solids is: WS = W/ (1+w), in which W is total weight. the equation for dry density is: pd = p / (1+w), in which p is bulk density, calculated as mass divided by volume. The equation for unit weight of dry soil is: yd = y / (1+w), in which y is unit weight. The equation for porosity is: n = e /(1+e), in which e is the void ratio. Finally, the equation for void ratio is: e = n/ (1-n), in which n is porosity

Compare the values of specific yield for some common materials, like sand, clay, gravel, and shale, and describe in general the factors affecting specific yield

Specific yield refers to a volume of water that a mass of saturated rock or soil will produce, solely by gravity, compared to the total volume of the rock or soil. Specific yield is represented as a percentage. As the relative grain size of a rock or soil increases, so should the specific yield of that rock or soil increase. Also, some geologic materials contain charged ions that cause an increase in adhesion of water. Shale and limestone both have a specific yield of between 0.5% and 5%. Clay has a specific yield of between 1% and 10%. Sandstone has a specific yield of between 5% and 15%. Sand has a specific yield of between 10% and 30%. A mixture of sand and gravel has a specific yield of between 15% and 25%. Finally, gravel has a specific yield of between 15% and 30%.

Compare the applications of the following types of electric logging: SP, resistivity, gamma ray, neutron, and caliper.

Spontaneous potential (SP) logs and resistivity logs are used to obtain information about subsurface structure. Resistivity logging involves electrodes spaced at a constant distance that are moved along a profile (borehole) resulting in vertical variations in resistivity being shown. The test shows the existence of faults that have thrown strata of different resistive properties in different positions. Similar relationships can be used in the identification of an anticline, a syncline, or an underground channel. Spontaneous potential logs can provide insight into the types of fluids present. Caliper logging records the diameter throughout the length of a borehole. Gamma ray logging is a method of logging boreholes by observing the natural radioactivity of the rocks through which the hole is in contact with. It was developed for logging holes that cannot be logged electrically because they are cased with conductive metal. Neutron logging is a method used in boreholes in which a radioactive source provides neutrons that enter rock formations and induce a radioactive response that can be measured.

Tell whether spontaneous potential, resistivity, or gamma ray logs would be high or low for substances you might encoutner in large quantities below the surface.

Spontaneous potential (SP), resistivity, and gamma ray values are all important parameters of down-hole characteristics collected during electrical and geophysical studies performed in test drilling. These parameters are plotted graphically as a function of depth and displayed on well logs. Relative values for spontaneous potential, resistivity, and the gamma ray logs for common subsurface materials are as follows: - salt water: low to moderate spontaneous potential, low resistivity -limestone: low spontaneous potential, high resistivity, low gamma - sandstone or sand: high spontaneous potential, moderate resistivity, low gamma - shale or clay: low spontaneous potential, low resistivity, high gamma -clay: low spontaneous potential, very high resistivity, low gamma -hydrocarbons: extremely high resistivity - freshwater: low spontaneous potential, high resistivity

Explain how a Stiff diagram, or a butterfly diagram, is set up

Stiff water quality diagrams are a useful tool in understanding groundwater chemistry. Stiff diagrams are also called butterfly diagrams. They are used to show the concentrations of abundant anions and cations plotted against each other graphically with the cations on the left and anions on the right. The centerline in a Stiff diagram is the baseline from which graphic representations of the proportions are graphed in millequivalents of each ion. Values for ions that were not detected are plotted as the detection limit or zero if no detection limit was reported. This graphical display of major ion chemistry is used for visualization of aquifer water populations and dynamics. Alternative constituents can be substituted into the diagram to illustrate many differing groundwater issues. The Stiff diagram is a powerful graphic based tool for investigating various relationships between major ions and trace elements in a groundwater system. The diagram can be enhanced by adding constituents of concern, physical measurements such as pH or temperature, and non-chemical values such as water level.

Discuss how the storativity, or storage coefficient, is calculated for an unconfined aquifer.

Storativity, otherwise known as the storage coefficient, is the volume of water released per unit area in an aquifer per unit decline in hydraulic head. It represents the vertically integrated specific storage value for an aquifer or aquitard. Storativity of an unconfined aquifer is the average amount of water that the aquifer either releases or stores for each unit area in response to a change of the hydraulic head by one unit. The following equation is used to calculate storativity: S = +-Vw/A * dh where S is storativity, Vw is the amount of water in storage, A is the area of the aquifer, and dh is the change in head. In general, the storativity values for unconfined aquifers are between 0.01 and 0.3.

Discuss what sress is and how it is commonly expressed in a drawing

Stress is a measure of force per unit area within a body. It is a body's internal distribution of force per area that reacts to external applied loads. Stress is often broken down into its shear and normal components as these have unique physical significance. In short, stress is to force as strain is to elongation. When discussing soils, stress is defined as the amount of force that nedds to be applied per unit area in order to cause a certain amount of deformation. A normal or compressive stress is considered positive when it points in the direction of the object; a parallel or shear stress is considered positive when it tends to place the object in a counterclockwise rotation. When drawn, stresses are divided into three vectors, one for each of the three dimensions

Review the factors that contribute to subsidence.

Subsidence is the sudden sinking or gradual downward settling of the Earth's surface with little or no horizontal motion. The movement is not restricted in rate, magnitude, or area involved. Subsidence is many times caused by the activity of humans. Human caused subsidence can be related to subsurface mining, oil extraction, or the pumping of groundwater. Underground and near surface coal mining is especially susceptible to subsidence as the sedimentary host rocks are seldom competent. Hard rock minig related subsidence can be severe near stoped areas or buried shafts/adits. Removal of large amounts of oil or gas from a section can cause subsidence. Occasionally urban or suburban planners are challenged by subsidence from abandoned mines. Subsidence may also be caused by natural geologic processes, such as dissolution, thawing, compaction, slow crustal warping, or withdrawal of fluid lava from beneath a solid crust.

Review the timing of North American orogenic events that formed features in the Eastern Unites States

The Appalachian Mountains of the eastern USA are the product of several orogenic events that culminated in the construction of the supercontinent Pangaea. During the early Paleozoic, the continent that would become North America straddled the equator. The Anti-Atlas Mountains of Morocco and the Appalachian Mountains were formed on the supercontinent of Pangaea and were subsequently separated by the opening of the Atlantic Ocean at 220 million years ago. The first mountain builiding episode, the Taconic Orogeny, occurred during the middle Ordovician period. Mountain building continued during the next 250 million years with the Caledonian, Acadian, Ouachita, Hercynian, and Allegheny orogenies contributing to produce a mountain belt as great as the Himalayan mountain range of today. Pangaea began to break apart in the early Mesozoic era as rifting produced the Atlantic Ocean. Since the separation of Pangaea, the eastern portion of North America has been a passive continental margin with erosion of the mountainous terrain and active formation of a coastal plain.

Define the following terms related to the designation of Atterberg limits: Atterberg limits, A-line, liquid limit, plastic limit, plasticity index, U-line

The Atterberg limits are a measure of the nature of a fine grained soil. Soil occurs in four states that are dependent on the water content: solid, semi-solid, plastic and liquid. In each of the four states the consistency and behavior of a soil is varied. Also affected are the soil's engineering properties. The following terms relate to the desingation of Atterberg limits: - Atterberg limits: the boundaries between the four levels of soil consistency: liquid, plastic, semi-solid, and solid - A-line: the division mark between clay and silt on the Atterberg plasticity chart -plastic limit: lower boundary of plasticity, upper boundary of semisolid - liquid limit: upper limit of plastic state, lower limit of liquid state - plasticity index: range in water content between liquid and plastic boundaries - U-line: mark or line dividing the upper limit of plasticity from the lower limit of liquidity

Review the role of the Dupuit assumptions in ground water investigations, and describe the Dupuit equation for flow in an unconfined aquifer

The Dupuit assumptions are used in ground water investigations and address unconfined consistent flow above a solid boundary. The Dupuit assumptions consist of the following premises: direction of groundwater flow is horizontal; hydraulic gradient is the same as the water table slope; and equipotential lines are vertical. These assumptions are then combined with Darcy's law to generate the following equation for flow in an unconfined aquifer: Q = 1/2 K * ht1^2 - ht2^2/l * w where Q is the flow rate, K is the hydraulic conductivity, ht1 and ht2 are the water table heights above the bottom boundary of the aquifer at the first and second wells, l is the distance between the two wells, and w is the width of the aquifer. The Dupuit assumption holds that groundwater moves horizontally in an unconfined aquifer, and that the groundwater discharge is proportional to saturated aquifer thickness.

Explore the composition of the Earth, with special attention to its layered structure

The Earth has an outer silicate solid crust, a highly viscous mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core. The crust of the Earth is composed of a great variety of igneous, metamorphic, and sedimentary rocks. The oceanic crust is different from the continental crust in that the former is from 3 to 6 miles in thickness and is mostly composed of mafic minerals. The continental crust is from 20 to 30 miles thick and is mainly composed of lighter silicate rocks. Below the crust is the mantle, an approximately 2900 km thick zone that comprises 70 percent of Earth's volume. The distinction between crust and mantle is based on chemistry, rock types, rheology, and seismic characteristics. The Earth's liquid outer core surrounds the inner core and is believed to be composed of iron mixed with nickel and trace amounts of lighter elements.

Review how High Altitude Landsat photos are collected and how they can be used.

The Landsat Program is the longest running enterprise for acquisition of imagery of Earth from space. The first Landsat satellite was launched in 1972, the most recent, Landsat 8, was launched in 2013. Landsat 8 carries eleven spectral band scanners with spatial resolutions ranging from 15 to 100 meters. The wide band of collection allows for the production of varied imagery useful to many industries. Landsat data have been used by government, commercial, industrial, civilian, military, and educational communities throughout the United States and worldwide. The data support a wide range of applications in such areas as global change research, agriculture, forestry, geology, resource management, geography, mapping, water quality, and oceanography. Landsat 8 imagery can be blown up to scales approaching 1:50,000 without extensive distortion due to lack of resolution. Landsat 8 is slaed to be replaced by Landsat 9 in the year 2023.

Explain what Mohr coulumb failure envelope is, and how it can be determined for soil samples.

The Mohr-Coulumb theory is used in soil engineering to define shear strengths of soils at different effective stresses. Coulomb's friction hypothesis describes and determines the combination of both shear and normal stress that will cause a material to fracture. A soil failure envelope, also known as a strength envelope, is an indication of the maximum amount of shear stress that a soil can withstand before fracturing. This level can be determined by plotting the experimental results of a strength test on a Mohr plot axis. Failure envelope can be calculated with the following equation: s = c + sigma(subscriptn) tan (phi) where s is shear strength, c is cohesion, sigman is normal stress at failure, and tan phi is the coefficient of internal friction

Discuss how you would descriptively determine rock hardness in the field using a pocket knife, and how you would classify material

The Mohs Hardness scale can be estimated in the field with a steel-bladed pocket knife. The Mohs scale indicated the relative hardness of mineral by observing their scratch resistance. Units of Mohs hardness are expressed with numbers ranging from 1 through 10. Each number indicated mineral hardness based on ability to scratch any other mineral with a lower ranking number. A ranking from softest to hardest of common minerals in the Mohs scale is: talc(1) ranging upward in hardness through gypsum (2), calcite (3), flourite (4), apatite(5), orthoclase(6), quartz(7), topaz(8), corundum(9), to the hardest, diamond(10). A steel-bladed pocket knife has a hardness between 6 and 7 and will scratch feldspar but will not scratch quartz.

Discuss the National Primary Drinking Water Regulations and the secondary standards, with attention to how they are used and how they are established

The National Primary Drinking Water Regulations (NPDWR), or primary standards, are designed to maintain a high quality of water in the public drinking water supply. The NPDWR's are legally enforceable. They set the level of harmful contaminants that can be allowed in drinking water, and categorize contaminants in terms of inorganic and organic chemicals, disinfectants, disinfectant byproducts, microorganisms, and radionuclides. Maximum contaminant levels for inorganic, organic, and disinfectant byproduct chemicals are established. Also, certain treatment techniques for reducing the levels of disinfectants and microorganisms are described. The National Secondary Drinking Water Regulations (NSDWR) are non enforceable guidelines regulating contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. EPA recommends secondary standards to water systems but does not require systems to comply.

Explain what RCRA stands for, and how it applies to geologists.

The Resources Conservation and Recovery Act of 1976, known by the acronym RCRA, is designed to protect the public from the disposal of hazardous wastes. Specifically, this law promotes waste reduction, reuse, and recycling. Hazardous waste is defined as waste that poses substantial or potential threats to human health or the environment and generally is flammable, oxidizing, corrosive, toxic, or radioactive. Hazardous wastes are incorporated into lists published by the Environmental Protection Agency organized into three categories. The categories are: non-specific source (F-List) wastes, source specific (K-List) wastes, and discarded wastes (P- and U-List). It is essential that geologists know that there are many exempted hazardous wastes such as mining overburden returned to the mine site, oil and gas wastes, and wastes from the beneficiation and extraction of ores and minerals, including coal.

Describe how faults can be interpreted from a map that does not include topography

The Rule of V's can be utilized to analyze fault orientation on a geologic map that does not include topography. Valleys will always be at the lowest topographic point because rivers and streams flow downhill. Faults which cross a valley will trace a V-shape outcrop pattern depending on the dip angle of the fault. The general rules are the wider the V-shaped outcrop pattern, the steeper the dip of the fault crossing a valley, and that the V-shaped outcrop pattern always points in the direction of dip. If the V-shaped outcrop of a fault points downstream, the dip of the fault is downstream and greater than the gradient of the valley. If the V is wide and points upstream, it indicated that the dip of the fault is upstream and steep. The outcrop pattern produced by a fault with vertical dip will be straight line across the valley. Whether the fault is normal or reverse cannot be determined by the Rule of V's. This information must be obtained from map notation or by analysis of geologic units in contact across a fault. Low angle fautls such as thrust faults or detachments will produce much tighter V-shaped outcrop patterns across drainages.

Define SPOT images (Satellite Pour I'Observation de la Terra) and describe the processing that each image level undergoes. Also discuss the uses of these images.

The SPOT satellite is a high-resolution, optical imaging earth observation satellite system operating from space. The program was initiated by the French in the 1970's. The SPOT program has launched 5 satellites to date. The program was designed to improve the knowledge of the earth by exploring the earth's resources and for detecting and forecasting phenomena involving climatology. The satellites also monitor human activities and natural events. The SPOT system includes a series of satellites and ground control resources for satellite control and programming. SPOT images come in green, red, and near infrared bands. These images can be stereo-paired to produce three-dimensional images. Level 1a images are used for stero plotting and radiometric studies. Level 1b images are used for thematic studies and photo interpretation. Level 2a images are used for standard cartographic projections. Level 2b images provide slightly more accurate cartogrpahic projections. The images produced by SPOT systems have a resolution of between 10 and 20 m. The satellite used to take these images orbits the Earth once every 26 days.

Discuss how Shuttle Radar Topography Mission (SRTM) images are generated and what they can be used for

The Shuttle Radar Topography Mission (SRTM) is an international research effort for obtaining digital elevation models on a global scale. This was initiated to generate the most complete hihg-resolution digital topographic database of Earth to date. SRTM consisted of a specially modified radar system that flew onboard the Space Shuttle Endeavor during the 11-day STS-99 mission in February of 2000. Shuttle Radar Topography Mission images are taken using the techniques of radar interferometry. The technique involves radar waves that are sent out from different locations reflecting off the surface. These signals are then picked up by a single detector. The amount of interference in the received waves gives an indication of the topography. SRTM images are capable of providing a three-dimensional topographical view of the Earth. The vertical image resolution of an SRTM image is 90 m.

Discuss TEGD guidelines for characterizing a water quality monitoring site

The TEGD documents best management practices (BMP's) for appropriate methodology of site characterization. The document is designed to alert the designers and drillers of a groundwater well to the potential risks of contaminating an aquifer relating to well construction and operation. In a site characterization, the uppermost aquifer is considered to be those interconnected pockets of water that have the potential to carry contamiantion further. In order to complete a comprehensive site characterization, the subsurface geology and hydrology must be studied. The range of data collection methods for this document include the following: soil borings, subsurface material tests, slug tests, pump tests, geophysical surveys, piezometer tests, and location of monitoring wells.

Discuss the TEGD-recommended methods for logging monitoring wells

The TEGD emphasizes that all test and monitoring wells should be comprehensively logged. Geophysical logging shall be conducted and documented in accordance with TEGD requirements. The following logs are required: one successful natural gamma ray or gamma gamma log for the full depth, (top to bottom of test hole); one successful neutron log in the fluid filled portion of the hole, (top to bottom of test hole); one successful (top to bottom of test hole) spontaneous potential (self-potential) log; and one successful (top to bottom of test hole) resistivity log. Log interpretations shall be made by a qualified person. TEGD requirements also call for a detailed geological log of all monitoring wells.

Summarize TEGD recommendations on monitoring well placement.

The TEGD provides an outline of accepted array design, placement, and construction of monitoring wells. The document stipulates that the monitoring well system should have at least three down gradient wells and one up gradient well. The three down gradient wells should be placed in order to intercept any contaminants moving through the system. According to the TEGD placement of monitoring wells should be based on dispersivity, hydrogeology, and seepage velocity. The targeted stratigraphic horizon or horizons containing the flow and the physical and chemical aspects of perceived hazardous materials will determine the vertical sampling intervals of the wells.

Describe how TEGD relates to RCRA, and briefly review the topics TEGD covers.

The Technical Enforcement Guidance Document (TEGD) was composed by the Environmental Protection Agency (EPA) in order to describe the process for monitoring the supply of groundwater. This document is designed to facilitate and maintain purity standards laid out in the Resource Conservation and Recovery Act of 1976 (RCRA). The document includes instructions for well design and overarching parameters for groundwater well construction, operation, and management. The TEGD also includes lists of acceptable materials in the drilling of groundwater wells. It also prescribes a method for analyzing and monitoring groundwater wells and describes the statistical analyses that should be performed to maintain quality during the drilling of groundwater wells.

Give the Theis equations and explain how they are used.

The Theis equations are: s = Q/4piT*W(u) u = r^2S/4Tt where s is the drawdown, Q is the volumetric discharge rate, T is the transmissivity, W(u) is the well function, u is a dimensionless time parameter, r is the distance from the well to the point of measurement, S is the storativity, and t is the time since pumping began. The Theis equations are used to determine transmissivity (T) and storativity (S) by inverse modeling. All parameters except T and S are measured or observed from the well. A mathematical analysis is then performed to determine the best-fit values of S and T for the well.

Discuss the most common map scales used by the USGS and describe what each map size is best used for

The USGS releases maps at standardized scales for products with various types of uses. Very small scale maps that depict the entire United States are often prepared at a scale of 1:3.5M or approximately 1 inch equals 55 miles. Advances in computer cartogrpahy have allowed for immense increase in detail at such map scales. An example is a popular USGS digital elevation model map of the contiguous United States at this scale. State maps are typically prepared at the scale 1:500,000 allowing for the depiction of moderate detail. These maps are typically large format wall maps. Maps designed for more regional detail are released at scales of 1:250,000 or 1:100,000. These scales are common for compilation geologic maps. Individual topographic quadrangle maps are issued at the scale 1:24,000. These quadrangle maps are also called 7.5 minute quadrangles and are at the effective scale for detailed topographical and geological maps. Detailed geology is often mapped at this 1:24,000, 7.5 minute quadrangle scale and subsequently compiled into regional 1:250,000 scale geologic maps.

Discuss the general divisions found in the Unified Soil Classification System and provide the abbreviations associated with them

The Unified Soil Classification System (USCS) is a soil classification system used in the engineering and geology disciplines to describe the texture and grain size of a soil. The classification system can be applied to most soils and unconsolidated materials, and is represented by a two-letter symbol. The first letter in the classification system describes the grain size of the particles in the soil or aggregate as follows: (G) gravel, (S) sand, (M) silt, (C) clay, (O) organic. The second letter designation describes particle size and grading, (P) poorly graded (uniform particle size), and (W) well graded (diverse particle size), or (H) high plasticity, and (L) low plasticity. Soild can be classified into fairly small groups based on this two letter system.

The strike of a plane (a three point problem) can be determined with graphic methods. Review the basic premise of each method

The attitude of a plane can be uniquely determined if three points of elevation on the plane are known, provided that we assume a constant dip value. True north direction must also be known to produce an absolute attitude. In many geological situations this involves knowing the depth beneath the surface at three locatlities for a desired plane. The three points must be plotted on a 2-dimensional map at their precise locations and to scale with each other. A straight line is drawn connecting the deepest and shallowest points. The point along this line corresponding with the depth of the medium depth point is determined by drawing structure contours along the line. The projection method involves making a fold line and then projecting points as a cross section. The simplified projection method also involves a fold line, which is drawn between the high and low points and indicates the apparent dip direction. In the proportional method, the map scale is transferred onto the three points, and parallel lines are drawn to calculate strike.

Describe the method by which gamma radiation is measured and describe how the measurement is used

The basic method for measuring gamma radiation is with a scintillation detector. Scintillometers operate by the use of crystals that emit brief flashes of light when stimulated by radioactivity. These flashes of light are amplified and detected by a meter within the instrument. The more flashes, the higher the level of radiation. Gamma radiation is measured in terms of counts per second, counts per minute, pulses, or API units. Gamma ray logging is used in oil and gas exploration. A gamma ray log produces the radioactivity log curve of the intensity of broad-spectrum gamma radiation emitted from the rocks in a borehole. It is used for correlation, structural analysis, and for distinguishing shales, which are usually richer in naturally radioactive elements, from sandstones, carbonates, and evaporates. Amount of gamma raditaion induced is also a measure of hydrogen content. Gamma ray surveys are also used in uranium exploration, both in regional airborne surveys, and in more focused, property-scale ground surveys. Surface gamma-ray anomalies are further investigated for economic uranium mineralization by core drilling.

Differentiate between effective stress and total vertical stress, referring to where they occur and how they are calculated

The concept of effective stress is one of the most important contributions to soil mechanics. It is a measure of the stress on the soil skeleton (the collection of particles in contact with each other), and determines the ability of soil to resist shear stress. Effective stress (o') on a plane within a soil mass is the difference between total stress (o) and pore water pressure (u). The total stress o is equal to the overburden pressure or stress, which is made up of the weight of soil vertically above the plane, together with any forces acting on the soil surface (e.g. the weight of a strucutre). The e equation used to caculate total vertical stress (ov) is: ov = zy where z is the depth, and y is the total unit weight of soil

Discuss how the rock quality designation is defined, and compare the information provided by the RQD with the information provided with the Terzaghi number.

The designation of rock quality, known by the initials RQD, is performed by analyzing the rock core. In order to be suitable for analysis, the rock core must be at least 2 inches in diameter. RQD is the total length of all pieces of core that are twice the diameter of the core divided by the total length of the core; this value is expressed in terms of a percentage. - A rock in good condition has an RQD of between 75 and 90% - A rock in fair condition has a RQD of between 30 and 75% - A rock in poor condition has a RQD between 25 and 30% Another way of designating rock quality is with Terzaghi numbers, which place a rock on a scale of one to nine: nine is a swelling rock, and one is a hard rock

Describe the paleontological lines of evidence used to support a stratigraphic correlation

The discovery of one fossil or paleontological attribute is not sufficient evidence to proclaim a stratigraphic correlation. Any stratigraphic correlation must include an entire model of the formation of all rocks in area of interest. Paleontological evidence is supportable only when cross referenced to overlapping known fossil assemblages or environments that can be temporally or spatially matched. Modern paleontology defines ancient life by studying how long-term physical changes of global geogrpahy, paleogeography, and climate paleoclimate have affected the evolution of life. Paleontology is interested in ecosystem responses to changes in the planetary environment and to evaluating how these responses have affected patterns of biodiversity. For valid stratigraphic correlation based on paleontolgy, the researcher must establish a level of certainty by describing a fossil assemblage that takes into account flora, fauna, and depositional environments

Outline the steps required in both graphic methods available to solve depth problems

The easiest method of solving a depth problem is with trigonometry. There are two ways of doing this: - scaled cross section method: strike, dip direction, and perpendicular line from outcrop ot the point of interest should be drawn. Relationship between strike and traverse directions indicated the type of depth problem. Scale is used to measure the distance between dip angle, which is measured at the intersection of outcrop with traverse, and the point of interest, which is marked by a perpendicular line from the traverse direction intersecting the line of the dip angle - projection method: find a point where strike line projects under the point of interest. Then, subtract strike elevation from the elevation of the point

Describe how ground water velocity is calculated in ground water studies

The equation for groundwater velocity is derived from Darcy's law and the equation for calculating velocity of discharge through a pipe. Combining the two equations provides the expression: vd = Ki where vd is the discharge velocity, K is the hydraulic conductivity, and i is the hydraulic gradient. When an area with a high groundwater velocity is subjected to a group of contaminants, these contaminants will tend to separate more quickly than they would in an area with low groundwater velocity. Dispersivity is an empirical factor which quantifies how much contaminants stray away from the path of the groundwater which are carrying them

Describe some helpful strategies for correctly interpreting the types of faulting found on a map

The first step in interpreting faults on a geologic map is reading the map key. The key will include descriptions of all map symbol notation and explanations. On geologic maps, faults are often shown as much thicker lines than those used to show geologic contacts. Offset on faults can be shown by a bar and ball on downthrown side of the fault or by placing a "D" and a "U" on the downthrown and upthrown sides, respectively. Thrust faults will typically be notated with teeth on the upper plate. In the absence of map symbols, outcrop patterns can be useful in determining fault orientation and dip. Also very useful is the rule of V's wherein the outcrop pattern of faults in relation to the topography can be used to determine fault characteristics. Additionally, cross sections often display a vertical representation of sub-surface structure and are frequently laid out to show the attitude or style of major faulting. Plotting surface and subsurface data on an equal area stereonet is also very useful in interpreting faults.

List the top 10 hazardous substances on the CERCLA Priority List of Hazardous Substances for 2005 and classify the as inorganic, organic, biological, disinfection or pesticide contaminants. Mention the most likely source of each contaminant

The following 10 substances have been deemed the most hazardous by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) Priority List of Hazardous Substances for 2005 (in descending order): - arsenic: inorganic, originates in nature, pesticides, and herbicides -lead: inorganic, originates in nature, mining, and manufacturing -mercury: inorganic, originates in nature, combustion, and manufacturing - vinyl chloride: organic, originates in manufacturing -polychlorinated biphenyls: organic, originates in coolants and lubricants - benzene: organic, originates in petroleum and chemical manufacturing - polycyclic aromatic hydrocarbons: organic, originates in incomplete combustion -cadmium: inorganic, originates in manufacturing and cigarette smoke - benzo(A)pyrene: organic, originates in incomplete combustion and manufacturing - benzo(B)fluoranthene: organic, originates in incomplete combustion and manufacturing

Review the characteristics and formation of the major categories of sand-based depositional features: ripples and ridges, sand shadows and sand drifts, dunes, whaleback or sand levees, undulations and sandsheets

The following are major categories of sand-based depositional feature: - ripple/ridge: an uneven surface or area constructed of subparallel small-scale ridges formed at the interface between a fluid and unconsolidated sediments. Typically produced by wind action, subaqueously by currents, or by the agitation of wind action. Features trend at right angles or obliquely to the direction of fluid flow. - sand shadow/sand drift: elongated and tapering sand formations that occur behind obstructions due to deceleration and general diminishment of transport energy -dune: a hill-shaped deposit of sand attributable to eolian processes. Dunes occur in varying morphologies and sizes based on the dynamics of wind and particle sizes which formed them. Typically dunes are longer on the windward side where the material is pushed up the dune, and shorter on the leeward side, or slip face - whaleback or sand levee: a large sinuous ridge or elongated hill that runs parallel or subparallel to the direction of the prevailing wind - undulation: a small whaleback - sand sheet: a flat area characterized by ripples

List the most common types of inorganic contaminants, and provide their sources, and consequences

The following are the most common types of inorganic contaminants: -arsenic: originates in nature, pesticides, herbicides, insecticides, can result in cancer and enzyme malfunction - lead: originates in nature, manufacturing, mining, fossil fuels, can result in damage to the central nervous system and death - mercury: originates in nature, manufactoring, mining, and volcanic activity, can result in damage to a fetus and to an adult centrus nervous system - cadmium: originates in batteries, welding, and cigarette smoke, can result in long term kidney and digestive system damage - chromium: originates in manufacturing, can result in high tissue damage and cancer - white phosphorous: originates in nature and manufacturing, can result in liver, heart, and kidney damage - selenium: originates in nature and in the refining of copper, can result in damage to the central nervous system - nitrate: originates in fertilizer, maure, and sewage, can result in infant blood disorders - perchlorate: originates in rocket fuel, can damage the function of the thyroid gland

Define the different categories of water designated in hydrogeology: connate water, juvenile water, perched ground water, runoff, underflow

The following categories of water are designated in hydrogeology: - connate water: water that was incorporated into the interstices of a sedimentary rock at the time of sedimentation and deposition - juvenile water: water originating from the interior of the Earth that has never been introduced or circulated in the ground water system - perched groundwater: unconfined ground water separated from an underlying aquifer by an intervening unsaturated zone - runoff: that part of precipitation appearing in surface streams. May be caused by direct precipitation or by cyclical processes such as seasonal thaw of snow pack - underflow: groundwater that flows below the alluvial plane of a surface stream or beneath the stream bed. common in arid environments

Discuss the following depositional features associated with continental glaciation: till plain, ground moraine, swell and swale topography, outwash plain

The following depositional features are associated with continental glaciation: - till plain: a large area covered with ground or ablation moraine consisting of dominantly unsorted and unstratified drift. This generally unconsolidated material was deposited directly by and underneath a glacier without subsequent reworking by melt water. Consists of a heterogeneous mixture of clay, silt, sand, gravel, and boulders ranging widely in size and shape - swell and swale topography: a region created by thick deposits of till with clay content. Produces gently rolling topography. A swell is created by the advance of the glacier, while a swale is formed by the retreat of a glacier - outwash plain: proglacial melt water deposits consisting of unconfined sorted sediments; stream pattern depends upo angle of topography

Review the depositonal features formed by glaciers, and discuss whether they are caused by direct deposition or by glacio-fluvial/lacustrine processes

The following depositional features have been formed by glaciers: - moraine: a mound, elongate ridge, or other accumulation of unsorted and unstratified glacial drift. Typically composed of till deposited chiefly by direct action of glacier ice. Moraines produce a variety of topographic landforms that are generally independent of control by the buried surface on which the drift lies. Caused through direct deposition. - valley train: a linear accumulation of boulders and cobbles confined between two rock walls, moraines, or by unmelted ice. Caused through direct depositon - lacustrine plain: a large area characterized by lakes and proglacial deposits. Lakes may have dropstones if icebergs once floated in the lake. Other lakes associated with glaciers are supraglacial lakes and kettle lakes -knob and basin topography: mounds and hillocks of material scattered around small basins, formed by the deposition of glacial drift

Define the following descriptive and quantitaive terms often used to describe soil characteristics: toughness, unti weight, void ratio, degree of saturation, porosity

The following descriptive and quantitative terms are used to describe the characteristics of soil. Some of these terms also refer to the characteristics and interaction of pore fluid with containing soils: - toughness: the degree of stress that soil can suffer before fracturing -unit weight (y): weight of a soil plus water for every unit of volume - void ratio (e): the ratio of the volume of evacuated space to the volume of the solids in a sample of soil - degree of saturatio (Sr): the ratio of the volume of water to the total volume of void space - porosity (n): the percentage of the total volume of a rock or soil sample that is made up of void spaces

Explain the hydrologic budget equation, and disucss how it is used

The following equation, known as the hydrologic budget equation, has been developed to summarize the inflow and outflow of water in a specific basin: dSt = P - E +- R +- U where dSt is the change in total storage, P is precipitation, E is evapotranspiration, R is runoff, and U is underflow Underflow is calculated as groundwater inflow minus groundwater outflow. Runoff is calculated as stream inflow minus stream outflow. Because changes in soil moisture are so miniscule, it is usually neglected in this kind of summary. Geologists use the hydrologic budget equation (occasionally known as the water balance equation) to assess changes over time in a water basin or aquifer or for modeling and planning studies

Define the following erosional features associated with alpine glaciers: cirque, tarn, glacial polish, striations

The following erosional features are associated with Alpine glaciers: -cirque: an ampitheather-like topographic feature formed at the head of a glacier by erosion. Cirques formed in conditions which are favorable, for example in the northern hemisphere includes the nroth-east slope being in shade and away from prevailing winds. These areas are sheltered from heat, and thus, they encourage the accumulation of snow - tarn: a small but deep lake found in the basin of a cirque; created by the melting of a glacier head -glacial polish: a smooth surface located on bedrock and the results of abrasion and movement of glaciers - striations: multiple scratches or grooves, generally parallel, inscribed on a bedrock outcropping or surface by a glacial event

Discuss how wind erosion creates unique features such as yardang, ventifacts, pedestal rocks, blowouts, and desert pavement

The following features are created by wind erosion: - yardang: a ridge formed by the action of wind-abrasion in cohesive material - ventifact: colluvial material or large cobbles that have been highly polished or shaped by wind abrasion caused by airborne sand - pedestal rock: an isolated erosional remnant of rock supported by a thinner pedestal. Caused by differential erosion - blow out: a small cup- or trough- shaped hollow or depression that is formed by wind erosion on a sand dune or other unconsolidated deposit. Typically occurs in areas of shifting sand or loose soil where protective vegetation is absent, disturbed, or destroyed - desert pavement: a natural deposit of residual wind-polished pebbles, boulders, and other rock fragments that mantles a desert surface. Typically occurs in areas where wind action or sheet wash have removed all smaller particles

Define the different depression-related features found in karst terrain, and show how they are similar or different: sinkhole, sinkhole pond, swallow hole, polje, sinkhole/karst plain

The following features are found in the depressions of karst terrain: - sinkholes: round or roughly elliptical depressions ranging in diameter from a few feet to 100s of feet. Created by bedrock collapse or the dissolution of bedrock by groundwater - sinkhole pond: the result of clay clogging a developing or existing sinkhole resulting in the formation of a localized perched water table - swallow hole: the opening at the bottom of the sinkhole through which water can flow into a space below the surface -polje: a karst field or karst plain. Derives from the Slavic for field - sinkhole or karst plain: a region characterized by sinkholes or karst topography. Krs, a limestone plateau in the Dinaric Alps of northwestern Yugoslavia and northeastern Italy is the type locality for karst topography

Define the following types of downward movement of soil or rock: avalanche, fall, rotational slide or slump, topple, transitional slide.

The following five kinds of downward movement of soil or rock can occur: -avalanche: a large mass of snow, ice, soil, or rock, or mixtures of these materials, falling, sliding, or flowing very rapidly under the force of gravity - fall: the free falling or precipitous movement of a detached segment of bedrock of any size from a cliff or other very steep outcrop or slope - rotational slide or slump: a slide of homogeneous earth or clay in which the slip surface of failure closely follows the arc of a circle - topple: an overturning slope movement with a turning point below the center of gravity of the falling unit - translational slide: landslide displacement in which the components have not rotated relative to one another, so that features that were parallel before movement remain so afterwards

Discuss how the following parts of a tunnel relate to the ground surface: shaft, adit, stope, raise, drift, winze, crown, invert

The following parts of a tunnel all relate to the ground surface: - shaft: a vertical excavation, driven from the surface, that is typically of limited area compared to its depth - adit: a horizontal or nearly horizontal tunnel constructed into a hillside, typically at a level below a known ore body or coal seam, for accessing working or for dewatering of a mine - stope: any excavation in a mine designed for removing ore. Shape and size are determined by, and are directly related to, the physical dimensions or shape of the orebody - raise: a vertical opening in a mine driven upward from a tunnel level to connect with the level above. Typically does not connect to the surface - drift: an entry constructed into the slope of a hill that is usually driven horizontally into an ore body or coal seam - winze: a vertical shaft connecting two underground levels in a mine. Does not reach to the surface - crown: the curved roof of a tunnel excavation - invert: the floor or bottom of a closed water conduit, aqueduct, tunnel, or drain

Review the structures created by deposition associated with continental glaciation: drumlin, esker, kettle, kame, and kame terrace

The following structures are created by deposition associated with continental glaciation: - drumlin: elongated and symmetrically arranged hills of glacial drift which may have been formed by reworking of older glacial sediments. Some drumlins may be cut and formed from sedimetns that were confined by floating ice -esker: a narrow and sinuous ridge of graded sand and gravel deposited by streams that are supraglacial, englacial, or subglacial - kettle: a shallow bowl shaped depression formed when a large block of ice is stranded in outwash or mixed outwash and till during glacial degradation. Upon melting of the ice block the ensuing depression may become a kettle lake -kame/kame terrace: a low steep sided hill or mound composed of poorly sorted sand and gravel that was depostied by melt water cascading into crevasses near the melting edge of a glacier

Describe the following structures and explain how they are formed in karst terrain: natural tunnels and bridges, hum, cavern, travertine, dripstone, helictite

The following structures are formed in karst terrain by the actions of carbonate-rich groundwater seepage and dissolution/precipitation of minerals: - natural totals and bridges: formed by water that dissolves rock underneath karst terrain - hum: individual remains of hills left behind after the dissolution of rock - caverns: interconnected caves with many levels and extending in all directions - travertine: dense, finely crystalline limestone. Frequently massive and concretionary. Typically white, tan, or cream and commonly displaying a fibrous or concentric banded structure. Formed by chemical preciptiation of calcium carbonate from solution in surface and ground waters - dripstone: any cave deposit of calcite or other mineral formed by dripping water, including stalactites and stalagmites - helictite: a small thin structure formed by persistent but small quantities of water trickling out of a hole forming a distorted twig like lateral projection of calcium carbonate

Define the following terms used to discuss compression of soil materials: compaction, consolidation, relative compaction, settlement, shrinkage limit

The following terms and measurements are used to discuss the compression of soil materials: - compaction: involves increasing soil density by mechanically diminishing the spaces between particles. Natural compaction is also possible - consolidation: a gradual decrease in the volume of a soil combined with an increase in the density of the soil. Induced by compaction, crystallization, and cementation - relative compaction: the amount of compaction that occurs in relation to the moisture-density curve. This curve is also known as the compaction curve - settlement: the slow downward movement of constructed foundations caused by the slow compression of the soil underneath the foundation - shrinkage limit: the water content at which the volume of the soil is lowest

Define the following terms used in stratigraphy: fossil assemblages, index fossil, key beds

The following terms are commonly used in stratigraphy: - fossil assemblages: the collective group of fossils occurring in a rock or formation. The fossil assemblage is all flora and fauna existing together in a sample from which relative age determinations are made - index fossil: an individual fossil with a known and specific age range that is used to identify the particular sequence in which it is found. Frequently use with other index fossils to describe a more specific time range for a particular sample - key beds: a stratum that is well define or easily identifiable containing distinctive characteristics that can be used in correlation of surface or subsurface mapping units. A key bed can be lithologic or based on fossils

Define the following terms, often used to describe the structural characteristics of undisturbed soil samples: homogenous, heterogenous, stratified laminated, fissured, honeycombed, slickensided, blocky, lensed, caliche.

The following terms are often used to describe and classify the structural characteristics of undisturbed soil samples: - homogenous : uniform composition throughout the sample, isotropic - heterogenous: variable composition, non uniform throughout, anisotropic - stratified: contains visible different layers, parallel bedding is evident - laminated: contains even and thinly bedded, parallel layers -fissured: easily broken along certain planes, fractured - honeycombed: marked by regular voids, evenly spaced - slickensided: smooth, polished surfaces due to shearing, indicated displacement direction and history - blocky: easily breaks down into your regularly shaped granules, which resist further division of soils - lensed: contains irregularly spaced, non- continuous pockets of material, typically terminated with tapered ends - caliche: white stained precipitate groundwater, contains calcium carbonate

Discuss the following terms and relate them to the anatomy of a landslide: crown, head scarp or main scarp, toe, flow

The following terms are related to landslides: - crown: the practically undisturbed material still in place and adjacent to the higher parts of the scarp along which a landslide moved - head scarp/main scarp: a relatively straight, cliff like face or slope of considerable linear extent which breaks the general continuity of the land. Separates surfaces involved in the landslide from those at higher elevations that were not involved in the event - toe: the farthest reaches of the bottom of a landslide. The zone of maximum extenet of runout - flow: a mass movement of unconsolidated material that moves in a plastic or semi fluid motion resembling a viscous fluid. Examples are: creep, solifluction, earthflow, mudflow, debris flow, and sturzstrom. Water is usually required for most types of flow movement

Define the following terms related to soil strength investigations: bearing capacity, consistency, critical void ratio, Mohr circle, Mohr-Coulumb equation

The following terms are related to soil strength investigations: - bearing capacity: the maximum load per unit area that a particular soil can be subjected to before it collapses. Bearing capacity is the ability of soils to support the loads imposed by buildings or structures - consistency: the general amount of cohesion in soil particles - critical void ratio: the void ratio of soil that stays the same even during shearing events - Mohr circle: a graph showing all of the individual stresses that act on a single point on a plane. The x-axis will indicate normal stress, while the y-axis will indicate shear stress - Mohr-Coulomb equation: calculates the amount of shear stress that causes a material to fracture

Define the following terms related to ground water quality: effluent, maximum contaminant level (MCL), reference dose, secondary maximum contaminant levels

The following terms are related to the quality of groundwater: - effluent: treated or untreated wastes that are released into the environment. May be a liquid, solid, or gaseous product discharged or emerging from a process - maximum contaminatn level (MCL): the maximum amount of contaminants allowed in water being reintroduced into a source of pubic water. The established MCL levels are based on health risks - reference dose: the amount of a chemical a human can be exposed to on a daily basis without suffering any adverse health consequences - secondary maximum contaminant level: the maximum amount of dissolved material in water that can have an effect on taste, appearance, or smell. Generally not subject to legislation

Define these types of engineered structures: berm, grout curtain, lagging, phreatic line, slaking

The following terms are types of engineered structures: - berm: a bench built into the sloping wall of an open pit or quarry to break the slope angle of an acceleration slope and to prevent and arrest rock fall or slide material - grout curtain: a pattern or grid of intersecting drill holes into which grout has been injected to form a barrier. Used around an excavations or under dams to form a zone through which ground water cannot seep or flow - lagging: used to secure the roof and sides behind the main timber or steel supports in a mine or excavation. This provides early resistance to pressure to discourage displacement of roof materials - phreatic line: the line or level of seepage. The upper water surface of the zone of seepage - slaking: crumbling and disintegration of rocks upon exposure to weathering related to air or moisture. Also refers to the breaking up of clay or soil when saturated with water, or of the effect observed in coal or clay-rich sedimentary rocks when exposed to air

Define the following terms used in ground water studies: hardness, hardpan, leachate, sodium absorption ratio, tracers

The following terms are used in groundwater studies: - hardness: the degree to which water contains concentrations of dissolved magnesium and calcium in ionic form - hardpan: a hard, impermeable layer close to the surface of the soil, caused by cementation and mineral precipitation; typical of acidic soils - leachate: a solution obtained by leaching. Water that has percolated through soil or rock containing soluble substances and that contains certain amounts of these substances in solution - sodium absorption ratio: the measure of the degree to which calcium in soil has been replaced by sodium. Expressed as a ratio. A soil with a high ratio is not appropriate for vegetation - tracers: chemial compounds that are introduced into groundwater flow that lend themselves to being detected, either chemically or visually. Used to document flow rates and flow pathways

Define the following general terms used to describe soil characteristics in engineering geology: bulk density, dry density, relative density, specific gravity

The following terms are used to describe soil characteristics in engineering geology: - bulk density (p): the weight of a soil for every unit of volume - dry density (pd): weight of a unit volume of dry soil after sample has been heated to 103 degrees Celsius - relative density (RD): the ratio of the difference between the maximum and actual void ratios for a soil; calculated with the equation: RD = (emax-e)/(emax-emin) where emax is the void ratio of a soil at its loosest state, e is the in situ void ratio, and emin is the void ratio of the soil at its densest state. Synonymous with specific gravity - specific gravity (Gs): the ratio of the mass of a soil to the mass of an equal volume of distilled water at 4 degrees Celsius

Discuss the terms used to describe soil grain size: well graded, gap graded, effective size, coefficient of curvature, coefficient of uniformity

The following terms are used to describe the grain size of soil: - well-graded soil: soil or unconsolidated sediment consisting sediment consisting of particles of several different sizes and having a unifrom or equal distribution of particles from coarse to fine. A graded sand or sandstone containing coarse, medium, and fine particle sizes in an example - effective size: corresponds with the weight percentage of material equal to a certain size amount. Measures the distribution of grain sizes; for example, a grain with an effective size of D30 would be finer than 70% of the other grains in the sample - gap graded soil: any soil that is missing distinct particle size ranges - coefficient of curvature (Cc): a measure of the curve on a grain size distribution plot - coefficient of uniformity (Cu): a measure of the degree to which grain sizes are uniform. Found by determining the ratio of particle sizes

Define the following terms used when describing stresses and strains on soils: stress, strain, effective stress, normal stress, shear stress, and shear strength

The following terms are used to describe the stresses and strains on soils: - stress (o): force per unit area placed on a soil - strain(E): an alteration in the shape or volume of a soil realted to stress. It is calculated as the ratio of the new shape compared to the original shape - effective stress (o'): the total amount of stress placed on a soil minus the pore-water pressure - normal stress (on): the component of total stress that acts perpendicular to the plane - shear stress (t): the component of total stress that acts parallel to any plane in question - shear strength (s): the degree to which a soil can resist shear stress; this is dependent on the cohesion of soil particles and friction

Explain the following terms that are used to describe the structure of soil related to mositure content: liquefaction, optimum moisture content, piping, seepage

The following terms are used to describe the structure of the moisture content in soil: - liquefaction: soild that transform from the solid state to a consistency of a heavy liquid as a consequence of increasing porewater pressure. Liquefaction is caused by the tendency of a soil to decrease in volume when subjected to cyclic undrained loading - optimum moisture content: the level of moisture required to reach the maximum dry density level of the soil. At this point any further addition of moisture increases the density of the soil - piping: erosion by percolating water in a layer of subsoil which results in caving and in the formation of narrow conduits, tunnels, or pipes through which soluble or granular soil material is removed. An example is the movement of material from the permeable foundation of a dam or levee by the flow or seepage of water along underground passages - seepage: the flow of a fluid through soil pores

Define the terms used to describe volume changes in soils: dilatancy, dry strength, quick condition

The following terms are used to describe volume changes in soils: - dilatancy: the tendency of a material to increase in volume when subjected to a shape change. Also refers to material which can assume a close-packed structure from a open-packed structure - dry strength: the resistance that a dry soil possess to being crushed. A soil that is composed of clays and gravels will have relatively high dry strength - quick condition: the tendency of some soil that lack cohesion to allow water to flow rapidly between grains and to liquefy the material. Such a soil does not possess significant bearing capacity. Bearing capacity is the ability of soils to support the loads imposed by buildings or structures

Define the following terms often used in discussing the geomorphic characteristics of a fault: fault scarps, scarplets, slickensides, breccia, mylonite

The following terms are used to discuss the geomorphic characteristics of a fault: 1. fault scarp: an escarpment or break in normal erosional topography caused by a line of faulting. A linear ridge caused by the upthrown side of a fault. 2. scarplet: a small fault scarp 3. slickensides: parallel grooves formed on the surface of a fault plane attributable to opposite movement of fault surfaces. Slickensides are striations or grooves on a fault surface 4. breccia: a coarse grained, unsorted, clastic rock composed of highly angular broken rock fragments in a fien-grained matrix. Typically lithified by secondary minerals. Can occur within the fault zone 5. mylonite: a dense chert-like metamorphic rock with a streaky or banded structure formed by shear stress. Typicallt lacking in cleavage. Mylonite is produced by the extreme pulverization and shearing of rocks that have been incolved in thrust faulting or intesne dynamic metamorphism

Define the following terms used in quantifying dissolved materials in groundwater studies: milliequivalent per liter, part per billion, part per million, picocuries per liter, total dissolved solids

The following terms are used to quantify the dissolved materials when performing groundwater studies: - milliequivalents per liter (meq/L): defined as concentration in milligrams per liter divided by equivalent weight. It is used to measure the concentration of all the solutes in a solution -parts per billion (ppb): parts per billion is a value representing concentration of a dissolved substance in a solution. One part per billion is equivalent in concentration to 1 microgram/liter (ug/l). Used to measure the mass of a solute as related to the total mass of the solution - parts per million (ppm): parts per million is a value representing concentration of a dissolved material in a solution. It is orders of magnitude more concentrated than ppb. One part per million is equivalent in concentration to 1 milligram/liter. Used to measure the mass of the solutes within the total mass of the solution - picocuries per liter (pCi/L): used to measure radioactive decay; 1 pCi per liter is the amount of material necessary to create 2.22 nuclear transformations every minute

Define these terms that refer to dams: abutment, cutoff, dam crest, freeboard, pressure relief well, random zones, spillway

The following terms refer to dams: - abutment: a surface or mass provided to withstand thrust as in the end supports of an arch or bridge or the terminal of a dam - cutoff: an impermeable wall or other structure placed within the abutments or beneath the base of a dam to prevent or reduce seepage loss. Typically developed in porous or fractured strata beneath or adjacent to a dam. It may be made of concrete, interlocking sheet piling, or grout injected in a pattern - dam crest; a dam's flat top - freeboard: the disance between the crest of a dam and the top of the water reservoid below - pressure relief well: a well drilled at the base of a dam that prevents seepage underneath the dam and relieves water pressure - random zones: any area within a dam where excavated materials are stored - spillway: a venue for the flow of water in the reservoir, which serves to reduce water pressure by allowing some water to go over or around the dam

Define the following terms: specific retention, specific storage, specific yield, storativity or storage coefficient

The following terms refer to the capacity of a well: - specific retention (Sr): the ratio of the volume of water that a body of rock or soil will hold against the pull of gravity to the volume of the body itself. It is usually expressed as a percentage - specific storage (Ss): the amount of water which a volume of aquifer will produce when a unit change in hydraulic head is applied to it. - specific yield (Sy): is the ratio indicating the volumetric portion of the bulk aquifer volume that an aquifer will yield when all the water is allowed to drain out of it with only the forces of gravity - storativity, also known as the storage coefficient (S): the volume of water that any permeable rock or soil releases or draws in for one unit of the surface area of the aquifer, for a unit change in head

Define the following terms related to the containment of water in underground structures: field capacity, hydraulic conductivity, transmissivity

The following terms relate to the containment of water in underground structures: - field capacity: The quantity of water held by soil or rock against the force of gravity - hydraulic conductivity: the ability of a porous rock or soil to transmit water. it is a factor of the rock or soil's permeability, as well as the viscosity of the fluid - transmissivity: the quantitative assessment of the ability of an aquifer to transmit water. It is the amount of water that can travel through one unit of aquifer with one unit of hydraulic gradient. Transmissivity (T) is related to prevailing kinematic viscosity, which is calculated T = Kb, where b is the saturated thickenss of the aquifer and K representing hydraulic conductivity

Define these terms, which relate to different materials that may be used in an engineered structure: grout, gunite, riprap, shotcrete

The following terms relate to the different materials that may be used in an engineered structure: - grout: a pumpable slurry of cement or a mixture of cement and sand that is forced into boreholes or crevices in a rock to prevent ground water infiltration. Frequently it is used to seal crevices below a dam or to consolidate and re-cement togethre broken or brecciated rock formations. Also called cement grout - gunite: a mixture of portland cement and sand that is applied through pressure using a specially adapted hose. It is frequently used in a sealing technique to preserve mine timbers and roadways, and as a fireproofing agent -riprap: a layer or series of layers of durable and angular rock fragments palced or fitted together. Its purpose is to secure a slope or to prevent erosion of a slope or face by waves or the action of water currents. If riprap is secured with concrete it is called grouted riprap - shotcrete: a mixture of portland cement and sand that commonly includes coarse aggregate (up to 2 cm)

Define the following terms relating to different types of ground materials: flowing ground, raveling ground, running ground, squeezing ground, swelling groung

The following terms relate to the different types of ground materials: - flowing ground: liquefied soil that is empalced or propelled by seepage into a tunnel or excavation due to a lack of soil cohesion or adequate sealing - raveling ground: rock that breaks into small round pieces when being drilled that tends to cave into the hole when the drill string is pulled. Rock or soil that forms agglomerated particles that bind a drill string by becoming wedged between the drill rod and the borehole - running ground: soil that is cohesionless. May be semiplastic or plastic and is typically seen in wet clays. These soils readily deform under pressure and squeezing into openings and crevices. These soils may enter a mine tunnel once the roof and wall supports have been removed - squeezing ground: any soil or rock that after entering a mine excavation or tunnel which is seen to maintain a constant volume - swelling ground: any rock or soil which undergoes a volume increase after excavation. Typical of many clay rich soils or formations

Define the following terms relating to earthquake hazards: seismic zone factor, maximum capable earthquake, response spectrum, time history

The following terms relate to the hazards of earthquakes and could occur on earthquake hazard maps, reports, or emergency response documents: - seismic zone factor: the number assigned to every seismic zone on a hazard map corresponding to the estimated highest amount of ground accelerations; these numbers are used when determining locations for structures - maximum capable earthquake: an estimation of the greatest possible earthquake that could be expected to strike a particular location; expressed as a probability of occurrence - response spectrum: a graphical depiction of ground motion, in which spectral acceleration is plotted against period - time history: ground acceleration over time calculated for a particular location during an earthquake event. It is used to develop a response spectrum

Distinguish between the following types of tests: direct shear test, triaxial test, unconfined compressive strength test

The following tests are desgined to quantify engineering parameters of soils: - triaxial test: a common method to measure the mechanical properties of many deformable solids. The test is used for soil, sand, clay, and other granular material. Test involves a cylinder of soil which is subjected to uniform fluid pressure from all sides. After being checked for deformation, the sample is then subjected to a vertical load. Drainage conditions are controlled - direct shear test: laboratory tests to measure the shear strength of soil in which the soil or rock sample is surrounded with sand and subjected to a series of mechanical stresses which are analyzed by computer. The sample is normally saturated before the test is run, but can be run at the in-situ moisture content - unconfined compressive strength test: similar to a triaxial test but without external confining pressure applied

Review the types of information that can be gathered from an undisturbed soil sample, collected with a thin-wall type sampler, or a disturbed sample, from a test pit.

The following tests can be performed on an undisturbed soil sample: compressibility, compaction, consolidation, density, and shear strength. Undisturbed soil samples can be collected with a Shelby tube or other thin-walled-sampler. The soil material can be extracted from the sampling tube and examined intact. The primary advantage of undisturbed soil samples lies in the fact that original stratigraphic relationships are maintained. This allows for observation and testing of original soil horizons and affords in-situ information not obtainable from disturbed soil samples. Shear strength tests on undisturbed soil samples are especially relevant as this will provide a profile across a desired area. Soils may also be obtained directly by grab or channel sampling from an exposed test pit wall. These are disturbed samples and can be tested for constitutents and some structural elements. Tests on disturbed soils include: grain size distribution, expansion data, bulk density, and Atterberg limits.

Distinguish amoung the following types of tests used in hydrogeolgoical investigations: packer test, percolation test, pumping test, slug test

The following types of tests are used in hydrogeological investigations: - packer test: used to assess the permeability of a section of rock. A short expansible-retractable device is deliberately placed in a well bore at a set interval to prevent upward or downward fluid movement - percolation test: assesses the appropriateness of a region for a septic sewage system or structure. It is performed by digging a hole of known dimensions and filling it with water. Time needed for drainage is then recorded -pumping test: used to define aquifers. Involves pumping a well for a defined period of time and measuring the change in the hydraulic head of the aquifer - slug test: assesses transmissivity, conductivity, and storage capacity of wells through water being added or removed from a well. The well response is then observed

Explain the following valley features observed in alpine glacier regions: glacial trough, glacial steps or stairways, paternoster lakes, hanging valleys, fjords, trough lakes

The following valley features are observed in alpine glacier regions: - glacial trough: a valley with precipitous sides coming down from a cirque - glacial step/stairway: a series of ice steps that connect a cirque with the end of a glacial trough. Steps are created by downhill-moving glaciers that differentially erode layers of bedrock - paternoster lakes: a group or collection of lakes found on glacial steps - hanging valley: a tributary glacial valley that has been stranded or had its streambed undercut by the mainstem glacier, producing a steep cliff. After glacial retereat, a waterfall frequently connects hanging valleys to mainstem stream - fjord: a glacially U shaped valley that has been flooded by seawater and is open at its mouth to the ocean - trough lake: a glacial trough filled with water, but above sea level

Both particle deposition and lava flow are affected by gravity, and so they can be used to locate the top or bottom of a bed. Discuss the features formed by each process and how they can help orient a bed.

The geologist can determine the vertical orientation of a rock bed by the orientation of lava flow structures, or by observation of particle deposition. Because these processes are dependent on gravity, rocks displaying these structures can usually be reoriented and can provide a great deal of information about prior vertical orientation. Graded bedding in which large particles give way to particles with decreasing size in individual beds are a common sedimentary feature recognizable and helpful in strata re-orientation. Lava flows contain very indicative internal structures such as crude graded bedding and an alternation of dense flow rock with vesicular flow top rocks. Both of these gravity-related structures can be recognized and used to re-orient lava flows. Packages of successive lava flows display an alternating pattern of dense and vesicular lava that can aide in reorientation.

Review the classifications of ground water (ranging from fresh to bring) based on TDS

The groundwater classifications based on total dissolved solids (TDS) are as follows: freshwater is defined as any water with a TDS of less than 500 parts per million (ppm). This value corresponds with the safe drinking water threshold for human beings. Groundwater with TDS values between 500 ppm and 35,000 ppm is considered brackish water. Saline groundwater contains total dissolved solid values between 35,000 and 50,000 ppm. Any groundwater with a TDS greater than 50,000 ppm is considered to be brine. Only three percent of the water on Earth is fresh water, and about two-thirds of this is frozen in glaciers and the polar ice caps. Of the remaining one-third, only 0.3 percent is represented by surface water. The remainder is represented by groundwater.

Explain how ground water inventory equation, and discuss how it is used

The groundwater inventory equation can be regarded as a stripped down version of the hydrologic budget equation. In the groundwater inventory equation, the only terms that are used are groundwater input and output: dS = I - O where dS is the change in aquifer storage (usually reported in acre-feet or gallons per year), I is the input to an aquifer, and O is the output or discharge from the aquifer. In order for this equation to be effective, input and output must be expressed in the same units. If the change in aquifer storage is positive, this indicates that the aquifer is growing. The groundwater inventory equation is used to assess on-going health of an aquifer or for annual monitoring.

Explain what information the hydraulic gradient provides in aquifer studies, and discuss how to calculate it.

The hydraulic gradient is the change in hydraulic head per unit of distance along the flow path between two points. As such, hydraulic gradient represents the slope of the water table between two well.s Hydraulic head is a specific measurement of water pressure or total energy per unit weight above a datum. Hydraulic head is usually measured as a water surface elevation and indicates the energy at the bottom of a piezometer. The hydraulic gradient between two points can be calculated with the following equation: i = dh/l = h1-h2/l where i is the hydraulic gradient, dh is the difference in head (h) between points 1 and 2, and l is the distance between two points. Hydraulic gradient measurements are important in defining changing aquifer characteristics through time.

Briefly define the following terms, all of which refer to karst-related subsurface disruptions: karst window, uvala, solution-subsidence trough, sinking creeks, sink, blind valley, solution/karst valley

The karstification of a landscape has the potential to generate many different features both on the surface and beneath it. Following terms all refer to karst-related subsurface disruptions: - karst window: any opening in a cave, sinkhole, or karst feature that penetrates to the surface -uvala: a karst window with a length greater than 1000 feet -solution-subsidence trough: a depression longer than 10 miles caused by subsidence and a solution along a fault -sinking creek: a creek or stream that starts on the surface and disappears underground - sink: the terminal end of the sinking creek - blind valley: a valley that terminates in a swallow hole - solution/karst valley: the type of blind valley located between surface and subsurface drainage

Explain what types of environments form economic deposits of coal

The largest collections of coal are in areas that used to be coastal plains, estuaries, or deltas, and subsequently became fresh or brackish swamps. Such swamps tend to accumulate huge amounts of organic matter, which over time becomes covered by water and other material to create a heated and pressurized environment for the formation of coal. The amount of time required for the formation of coal depends on climate and other factors. In North America, extensice inland seas during the Cretaceous era with repeated cycles of advance and retreat created the conditiions for extensive coal deposits. Extremely thick beds of coal occur in Colorado and Wyoming in Cretaceous coal sequences. Coal can occur in very unusual places such as interbedded with old lava flows.

Discuss the major causes of dam failures, and which types of dams are msot likely to fail.

The main causes of dam failure are: spillway desing error; geological instability caused by changed to water levels during filling or poor surveying; poor maintenance of outlet pipes; extreme rainfall; and human or computer design error. Dam failures are generally catastrophic if the structure is breached or significantly damaged. Routine monitoring of seepage from drains in, and around, larger dams is necessary to anticipate any problems and permit remedial action to be taken before structural failure occurs. Most dams include a mechanism that permits the reservoir to be lowered in the event of such problems. Embankment dams are probably the msot susceptible to failure as they are generally constructued of unconsolidated or grouted material. Concrete gravity arch dams are less prone to catastrophic failure due to their concrete construction.

Discuss the three main coal producing locations in the United States today; and cite the unique characteristics of coal from each region

The major coal producing regions of the United States are: the Appalachian Mountain region of eastern USA, the Midwest, and the Rocky Mountains. The Appalachian Mountain region is the major producer of bituminous coal in the USA. Large field of bituminous coal also occur in the MIdwest and along the Rocky Mountains. Most of the coal that comes from the Western states is lower grade sub-bituminous and lignite. In the Rocky Mountains, Wyoming produces the most coal of any state; however, Montana has the most coal reserves. The largest coal mine in the United States is in Wyoming. One of the largest deposits of anthracite coal is in northwestern Pennsylvania. Current coal reserves in the United States are 270 years.

Discuss some of the important factors regarding water quality for agriculture

The major water quality issues for agriculture involve potential problems and restricted use due to salinity, rate of water infiltration into the soil, and specific ion toxicity. Salinity is a factor due to a reduction in soil-water availability to crops. Recent research findings on plant response to salinity within the root zone have been updated and crop tolerance values have become available. A water infiltration problem related to water quality is usually associated with both the salinity and sodium content of the water. The potential water quality issue which causes an infiltration problem is based on a combination of the salinity (ECw) and sodium adsorption ratio (SAR) of water used for irrigation. Specific ion toxicity is a regional or site-specific problem which must be addressed on an individual basis.

Describe five methods that can be used to prevent salt water intrusion into a fresh aquifer.

The natural balance between freshwater and saltwater in coastal aquifers is disturbed by ground water withdrawals and other human activities that lower ground water levels, reduce fresh ground water flow to coastal waters, and ultimately cause saltwater to intrude coastal aquifers. A common approach for managing saltwater intrusion has been to reduce the rate of pumping from coastal wells or to move the locations of withdrawals further inland. Other alternative solutions for reducing groundwater withdrawals involve artificially recharging freshwater into an aquifer. This acts to increase groundwater levels and to hydraulically control the movement of the intruding saltwater. In addition to more conentional methods, innovative approaches are now being used to manage saltwater intrusion including aquifer storage and recovery systems, desalination systems, and blending waters of different quality.

Describe how subaerial volcanic deposits form and what types of conditions and minerals are associated with them.

The predominant economic deposit associated with subaerial volcanism are industrial minerals and construction products. The most important industrial mineral deposits associated with volcanic events include kaolin, bentonite, zeolites, and scoriaceous cinders. All of these mineral resources occur as alteration products of volcanic rocks associated with subaerial eruptions. Kaolin it is found in pyroclastic flows and ash flow tuffs. Bentonite occurs as stratiform mineral bodies within poor welded pumice rich and ash rich layers. Zeolites deposits are distal to volcanic vents. Volcanic cinders and other scoriaceous products of subaerial volcanic eruption are important as filler for cinderblocks and other uses. Epithermal hot spring type gold/silver and base metal deposits are sometimes related to subaerial volcanism and are somewhat less economically important, although a few deposits are of exceptionally high grade. These deposits can also contain native mercury

Explain how a seismic refraction survey can help assess rippability of subsurface rock.

The rippability of Earth materials is defined as a measure of the relative ease with which a geologic or earth material can be dislodged by rippers or rigid steel teeth. It measures the degree of ease with which a material can be excavated. The rippability of Earth materials is dependent on density and degree of weathering to which they have been exposed. Seismic refraction velocity can indicate these parameters. Highly weathered materials will be easier to excavate, because they already contain many voids, fractures, and have been partially decomposed. Rocks that contain very few fractures and discontinuities are extremely difficult to rip, and must be excavated by explosives. The seismic refraction velocity will tend to be the fastest through the rocks that have little discontinuity and weathering.

Describe the following types of electrical logs used in borehole geophysics: resistivity, normal resistivity, single point resistivity, and spontaneous potential

The specific resistance of the rock walls of the hole to electrical current is measured in the resistivity log. This is done by inserting a drill attachment containing electrodes into the borehole. Electrical resistivity is expressed in ohm-meters. There are two kinds of resistivity log. A normal resistivity log involves the insertion of four electrodes with a standard spacing. A single-point resistivity log, on the other hand, involves the use of only two electrodes, and can therefore only be performed on a limited area. The spontaneoud potential is the measure of the change in DC voltage between the surface and a particular point in the well. In general, differences in electrochemical potential between formations are responsible for the changes in spontaneous potential.

Review in detail the Standard Penetration Test (SPT) procedure.

The standard penetration test (SPT) yields data about the geotechnical engineering properties of unconsolidated materials. It is used to determine densities of unconsolidated deposits where it is impractical to obtain an undisturbed sample. The test is performed by driving a thick-walled sampler tube into the bottom of a drill hole with blows from a hammer. The standard hammer weight is 140 pounds, with a hammer fall distance of 30 inches. A counter determines the number of blows required to drive the sampler for each 6 inch intercals. If 50 blows are insufficient to advance sampler 6 inches, the distance penetrated at 50 is recorded. Blow counts are totaled for the 3nd and 3rd 6-inch intervals into the N-value, or CN = 1/sqrt(sigma prime v), in which sigma prime v = the effective overburden pressure (Tons/ft^2), and CN*Nfield =Ncorrected. The corrected blow count (Ncorrected) is the number used to compare results from different soils. The SPT is used to assess and compare earthquake liquefaction hazard in sandy unconsolidated materials.

Discuss the interpretation of standard penetration test results.

The standard penetration test is used to assess the relative density of subsurface soils. If the soil requires 15 or more blows before allowing 12 inches of sampler penetration, it is considered to be very stiff or hard. If 10 to 15 blows are required, the soil is considered to be stiff. A moderately stiff soil will require only 4 to 10 blows. A moderately stiff soil will allow a person to penetrate to a depth of 1 to 2 inches with thumb pressure. A soil that allows 12 inches of sampler penetration in 4 or fewer blows can be classified as a very soft soil, and is probably composed of sand, silt, or clay.

Describe what information the step-drawdown test provides that cannot be provided by other tests like the constant-rate pumping test. Compare it to the variable-rate drawdown test.

The step-drawdown test provides information about storage coefficient and transmissivity of a well that describes the specific capacity of the well and its fluctuations during increased yields. The overall efficiency of the well is often measured with a step-drawdown test. The test is performed by gradually increasing the rate at which water is pumped out of a well. Drawdown is measured during each incremental increase in the rate of pumping. A constant-rate pumping test stimulates an aquifer or well through pumping and by observing the aquifer's response in observation wells. The constatn-rate pumping test is performed in order to measure the hydraulic conductivity, storativity, or specific yield of an aquifer or well. A slightly different test is the variable-rate drawdown test, in which the rate of withdrawal is manually changed. In this test, the optimum pumping rate and well depth can be determined more quickly.

Discuss what causes landslides, and group causative factors according to type

The term landslide covers a wide variety of mass movement and other gravity driven downslope transport processes involving the movement of soil and rock material en masse. Typically displaced material in landslides will move over a relatively confined zone or surface. Wide ranging slope angles and diversity of geologic materials of varying properties that affect resistance to shear, result in a great range of landslide morphologies, slide rates, and sizes. Landsliding is often preceded and followed by perceptible creep along the surface of sliding and/or within the slide mass itself. Terminology used to classify and describe landslide types generally includes the landform or material involved, as well as the process responsible for it. Some examples are: rockfall, translational slide, block guide, avalanche, mudflow, liquefaction slide, and slump.

Explain how geologic, chemical, and phenomenological information can be used to date geologic units

The thickness, composition, and sedimentation or emplacement patterns of a geologic unit can give clues to its age, as can stratigraphic position. Additionally, radiometrically dateable materials within a unit such as ash beds or meteorite impact events an occasionally provide an absolute date. Interbedded lava flows or intrusive sills within a rock sequence can help to unravel the history of the entire sequence if the index rocks have known dates or can be dated radiometrically. Sedimentation patterns can be analyzed to determine depositional environments which can aid in age determination. Chemical isotopes or fluid inclusions can be analyzed and used to determine the age of geologic materials or events. Weathering rates of geologic materials can be determined, in part, by chemical methods leading to age determination. Paleomagnetism is a method used for geologic dating, which utilizes a known fluctuation of the poles of the Earth's magnetic field over time and compares it to the remanent magentization found in th emagnetic mineralogy of a particular formation.

Describe how the Bernoulli equation is used to calculate the total energy of an aquifer

The total energy of an aquifer can be calculated using the Bernoulli equation: E = v^2/2g + z + P/y where E is the total energy loss or head loss (with units of length representing the energy from a column of water with that height), v is the velocity of groundwater flow, g is the acceleration due to gravity, z is the elevation of ground water above a reference mark, P is the pressure, and y is the specific gravity of water. Velocity head is a measure of energy relative to the amount of energy contributed by the motion of the groundwater. Elevation head is a measure of potential energy and is defined as the amount of energy that would be realized if the water was released from a given elevation. Pressure head is also a measure of potential energy reflective of the compressive energy stored within the water.

Describe the types of double-tube core barrel sampler that are used, and discuss how it is used and on what materials it works best.

The two basic types of double tube core barrel samplers are the Denison sampler and the Pitcher sampler. The Denison sampler features an outer barrel with a serrated leading edge, around an inner barrel with a smooth edge. The Pitcher sampler utilizes a self-adjusting inner barrel. The Denison sampler is used to obtain samples of hard soils or partially consolidated sediments. In the Denison design a smooth inner barrel pushes into the soil, aided by circulating drilling fluid, as the outer barrel slowly rotates dislodging the sample. The Pitcher sampler operates in a similar fashion with the exception that the inner barrel protrudes past the bit and adjusts itself in accordance with the hardness of the soil. Both of these kinds of samplers are suitable for un-cemented, slightly cemented, or extremely fine-grained soils.

Discuss the occurrence and consequences of the most common types of biological contaminants found in ground water.

The two most commonly occurring types of biological contaminants found in groundwater and in drinking water are the protozoa Cryptosporidium and Giardia lamblia. Cryptosporidium is typically found in lake and river water and in groundwater. Indigestion of this protozoa results in stomach cramps, nausea, and damage to the immune system. This protozoa is related to animal or human waste contamination of groundwater. It cannot be eliminated through chlorination, but only through boiling. Giardia lamblia is a protozoa commonly found in water, food, or soil that has been contaminated by animal feces. Contact with this protozoa can cause intestinal disorders like diarrhea, vomiting, and nausea. The following methods are appropriate for eliminating Giardia: boiling, micro-filtering, or introduction of iodine.

Discuss what stereo-paired low altitude photos are, and how they are used in geology

The use of low-altitude stereo-paired photographs is called stereoscopy. Terrain analysis through the use of aerial photography adds preliminary surficial and structural geologic information prior to field studies. Stereo-pair photographs are used in field geology to provide a 3-dimensional image during geologic mapping. Structure, lithologic contacts, and attitude symbols are transcribed directly onto the stereo-pair photos in the field as geology is ground checked. The 3-dimensional view allows the mapper to visualize the ground he or she is directly mapping. Stereo-pair photos are then directly put into a sterogrpahic plotter, either mechanical or digital, by which field notations can be placed precisely on a topographic base. As most topographic quadrangle maps are prepared using stereo-paired photographs, location of ground features will be optimized on to the topographic base.

Discuss how the standard well numbering system is modified for irregularly shaped sections

The usual system for well numbering assumes a square land division. The system used is the Township and Range system of the Public Land Survey. In many situations based on terrain irregularities or distortions in the PLS grid, sections of land or portions of townships will not be completely square. When section lines are not square, the standard 16 parcel quarter-quarter (1/4 1/4) section grid is put into alignment on the map by superimposing the lower right corner of the grid on the lower right corner of the section. Using this method some or all of the quarter quarter (1/4 1/4) section parcels will be less than 40 acres and will not be perfectly square. The positions of all lettered parcels will be located based on skewing of the overlay off right hand corner. However, it should be easy to determine the location of the parcel.

Define the following terms that refer to ground water locations: vadose zone, capillary fringe, water table

The vadose zone is the area between the ground surface and the saturated water table. The vadose zone is commonly known as the unsaturated zone. As the water in the vadose zone is less pressurized than atmospheric of adhesion and capillary action. Capillary action supports the vadose zone above the saturated water table. The capillary fringe is the zone in which groundwater seeps from the water table to fill pores upward into the vadose zone. In areas with good soil development with a wide range in pore size, the unsaturated zone can be several times thicker than the saturated zone. The water table is defined as the surface between the zone of saturation and the zone of aeration. The water table is the surface of a body of unconfined ground water at which the pressure is equal to that of the atmosphere.

The layers that make up sedimentary rocks vary in thickness. List the quantitative classifications used to describe sedimentary rock stratification, and describe (quantitatively and qualitatively) the way different rocks split

The variation in the thickness of layers in sedimentary rock is quanitifed by assigning named ranges of bed thicknesses. The following criteria quantify and name standardized bed thicknesses: >300cm = massive bedding 100-300cm = very thickly bedded 30-100cm = thick bedded 10-30cm = medium bedded 3-10cm = thinly bedded 0.3-0.1cm = thickly laminated <0.3cm laminated Sedimentary rocks will break apart according to their hardness and interal structure. Massively bedded rocks tend to be harder to break and have generally higher compressive strengths when tested in a laboratory setting. Thinly bedded or laminated sedimentary rocks tend to be fissile or friable in general and do not possess breaking resistance or high compressive strengths. Degree of cementation is a very important component as a mssive, poorly-cemented sedimentary rock could be quite friable and split easily.

Review the general strategies used to help prevent landslides.

There are a few basic ways to mitigate the possibility of landslide. Extremely steep grades can be minimized by recontouring and moving material from the crown to toe area, thus reducing the chance of a landslide. Descreasing saturation and pore pressure of soils by diverting surface water or adding dewatering wells, horizontal drains, or trenches, can minimize the risk of landslide. Monitor wells and piezometers can be installed to monitor interior dynamic of potential slide areas and to alert for potential landslide events. Architecturally, buttresses and retaining walls can be put in to stabilize unsteady slopes. Rocks that are considered to be unstable may be shored up with rock bolts, and soil can be hardened through thermic treatment or grouting.

Review the different types of boring methods used to sample soils

There are a few different methods utilized in soil sampling. The simplest method for determining soil thickness and composition is with either a metal penetration rod or a hand anuger. A flight auger is mechanically driven and escorts samples of soil out of the hole as it drills. These are to be considered disturbed samples but can be logged visually. To obtain an undisturbed sample auguring to the appropriate depth, removing the augur, and manually drawing the sample is the standard technique. A hollow-stem augur is used to obtain undisturbed soil samples without having to remove the augur from the hole. Sometimes, it may be useful to use a rotary wash drill, which uses a fluid to evacuate loose rock and soil from the hole.

Discuss how the steepness of a slope can be expressed

There are a few different ways to express the steepness of a slope. The most common way to express slope is as the ratio between the horizontal and vertical. It is commonly expressed, for example, as three-to-one (3:1), or two-to-one (2:1), with the vertical component of slope as one. Another way to express slope is as a grade, or as a ratio between vertical and horizontal slope; this is typically expressed as a percentage. The third and final way to express slope is to consider the angle of the slope as compared to the horizontal as measured with a slopemeter. The slope angle is calculated by considering the arctangent of the vertical extent divided by the horizontal extent.

Describe the different types of fault displacements, including heave, net slip, offset, strike separation, and throw

There are a number of different kinds of fault displacement. Both vertical and horizontal components of displacement may be active simultaneously. Horizontal movement along a fault is referred to as heave, whereas vertical movement is called throw. A number of specific measurements are made to determine displacement in faults. Net slip is the measure of the distance between two points that were adjacent before the first movement in a fault. A vector between these points indicates the distance and direction of fault displacement. Strike separation is measured across the strike of the fault, and is defined as the horizontal distance between each side of the fault. Offset, finally, is the component of displacement measured perpendicular to the strike of the disrupted side of the fault.

Discuss the composition of limestone, with special attention to the role that the depositional environment plays.

There are both clastic and nonclastic limestone. Clastic limestones are made up of calcium carbonate fragments that were deposited in place or were transported from elsewhere within the basin in which they formed. Chemically and biologically precipitated particles are classified according to grain size. Oolites are from 0.2 to 2.0 mm, pellets are limestones classified by the size of the clasts: calcirudites, calcarenites, or calcilutites. The clastic limestones form predominantly in a marine environment. Nonclastic limestones consist of chemically or biologically precipitated calcite or aragonite material that has not been transported since original deposition. Other limestone rocks in the nonclastic subclass such as reef limestone (stromatolite) and travertine, are named on the basis of texture and mode of formation. These limestones form in both marine and nonmarine environments.

Describe why calculating the total head for an unconfined aquifer is different than a confined aquifer.

There are differences in calculation of the total head for unconfined aquifers as opposed to calculation of total head for confined aquifers. In using the Bernoulli equation to calculate the total head in an unconfined aquifer, the pressure value must be set to zero. This is due to the fact that unconfined aquifers exist at atmospheric pressure and that there will not be any compressive energy to drive out the water. Since the velocity is also small for most aquifers, elevation head can be calculated with the following equation: h = z1-z2 where h is the head loss, z1 is the higher elevation head, and z2 is the lower elevation head

Review the four types of thickness problems, and outline the steps and information you would need to solve each using either the grpahic or trigonometric method

There are four basic types of thickness problem. Before any of them can be solved, the cross section in the dip direction perpendicular to strike must be drawn. The following terms are required in graphical solutions: thickness (t), outcrop width on the ground perpendicular to strike (w), dip angle(q), angle between strike and traverse direction (B), traverse distance across the outcrop (l), slope angle (o), and slope angle along the traverse (o1). The four scenarios are: - horizontal ground surface, outcrop width perpendicular to strike: t = w sin q - horizontal ground surface, outcrop not perpendicular to strike: t = l sin B sin q - sloped ground surface, outcrop width perpendicular to strike: T = w sin (angle) - sloped ground surface, outcrop width not perpendicular to strike: wither t = l (sin q cos o1 sin B - sin o1 cos q), if the slope and dip are in the same direction, or t = 1(sin q cos o1 sin B + sin o1 cos q), if the slope and dip are in opposite directions

Describe the four types of unconformities found in rock beds

There are four basic types of unconformity: nonconformity, disconformity, paraconformity, and angular unconformity. Unconformity that forms when granitic or metamorphic rocks are exposed to erosion and then covered by sedimentary rocks is called a nonconformity. If the older surface remains essentially horizontal during non-deposition, the plane formed between it and new sedimentation is called a disconformity. Visibly, a disconformity can look like continuous sedimentation. A paraconformity is an unconformity in which strata are parallel and the contact is a simple bedding place. If the old erosion surface is more complex and has been subjected to tectonic episodes, an angular unconformity can develop as sediments are laid down over tilted bedrock. This type of unconformity records not only missing time but changing geologic environments.

Compare the types of downward movements that may occur in geology: settlement, differential settlement, hydrocompaction, subsidence, soil creep, triggered creep

There are six kinds of downward movement that may occur in geology: -settlement: natural compaction or re-compaction in disturbed sediments - differential settlement: general downward movement or subsidence that occurs in differing areas of a structure at differing rates - hydrocompaction: the collapse or densificaiton of soil due to the effects of saturation or wetting - subsidence: the vertical settling of the subsurface of the Earth without or with only minimal horizontal motion - soil creep: the gradual, steady downhill movement of soil and loose rock material on a slope that may be very gentle but is usually steep - triggered creep: any slow movement downhill that occurs as a result of an externally applied force. For example, an earthquake

Differentiate between the three different types of modulus: bulk (incompressibility) modulus, shear (rigidity) modulus, Young's (elasticity) modulus

There are three different kinds of modulus, or ways to measure the stiffness of the material: - bulk modulus (K; otherwise known as incimpressibility modulus): a measure of a substance's resistance to uniform compression. It is defined as the pressure increase needed ot affect a given relative decrease in volume - shear modulus (G; also known as rigidity modulus): refers to the deformation of a solid when exposed to a force parallel to one of its surfaces as its opposite face is exposed to an opposing force. This will cause an object that is shaped like a rectangular prism to be deform into a parallelpiped - Young's modulud (E; also known as the modulus of elasticity): a measure of the stiffness of a given material. Defined as the ratio, for small strains, of the rate of change of stress with strain

Describe the three tests to determine dry strength, dilatancy, and toughness of soil samples

There are three tests performed to determine the basic characteristics of a soil sample: - In the toughness test, the sample is rolled into a cylinder about an eighth of an inch in diameter. The sample is then folded and re-rolled again. This process is repeated several times. When the plastic limit of the sample has been reached, it will becomes rigid and lose plasticity - In the dilatancy test, the sample is made slightly moist and is shaken latterly in the hand. If water beads up on the surface of the sample, it is considered dilatant -In a dry strength test, the soil is moistened until it has a consistency similar to putty. The sample is then dried out and broken. A soil with a high degree of plasticity will also have a high degree of dry strength

Explain how to calculate the degree of saturation

There are two different equations that can be used to express the degree of soil saturation. One equation is a rendering of the defintion of degree of saturation: Sr = Vw/Vv where Sr is the degree of soil saturation, Vw is the volume of water in the soil, and Vv is the volume of void space in the soil. The other way to calculate degree of saturation is as follows: Sr = wGs/e where w is the ratio of water contetn ratio, Gs is the specific gravity, and e is the void ratio. These three quantities are themselves calculated as follows: w - ms/ms; Gs = ms/VsPw; e = Vv/Vs where mw is the mass of water in the soil, ms is the solid mass of the soil, Vs is the volume of the solid, and ps is the density of the solid

List the three types of plate boundaries, and explain how they differ

Three types of plate boundaries occur depending upon the way the tectonic plates move relative to each other. Transfrom boundaries occur where plates slide past each other along transform faults. The relative motion of the two plates is either sinistral (left side toward the observer) or dextral (right side toward the observer). Transform plate boundaries produce devastating earthquakes. The San Andreas fault in California is currently a transform boundary. Divergent boundaries occur where two tectonic plates are pulling apart, as in mid-ocean ridges and zones of rifting. Convergent boundaries occur when two tectonic paltes are being pushed together. Typically one of the plates will be forced under the other creating a subduction zone. Convergent plate boundaries and subduction zones produce volcanic and plutonic activity.

Give the time-drawdown test equations for calculating transmissivity and storativity

Time-drawdown test equations: For calculating transmissivity in square feet per day: T = 35Q/ds For calculating transmissivity in gallons per foot per day: T = 264Q/ds For calculating storativity in square feet per day: S = Tt0/640r^2 For calculating storativity in gallons per foot per day: S = Tt0/4790r^2 where Q is pumping rate, ds is the change in drawdown (over one log cycle from the plot), t0 is the time at the zero-drawdown point from the plot, and r is the distance between the pumping and observation wells

Discuss the qualifications that allow a snow or ice field to be considered a glacier. Provide some examples of glaciers in the United States

To be considered a glacier, a snowfield must possess some of the following characteristics: a large mass of ice formed, at least in part, on land by the compaction and recrystallization of snow, moving slowly by creep downslope or outward in all directions due to the stress of its own weight, and surviving from year to year. Glaciers have an upper part that receives most of the snowfall called the accumulation zone. The depth of ice in the accumulation zpne exerts a downward force sufficient to cause deep erosion of the rock. On the opposite end of the glacier, at its foot or terminal, is the deposition or ablation zone, where more ice is lost through melting than gained from snowfall and sediment is deposited. the place where the glacier thins to nothing is called the ice front. Due to erosive forces at the edges of the moving ice, glaciers turn V-shaped river- carved valleys into U-shaped glacial valleys. In United States, glacier formations are found in Alaska, as well as in the Rocky, Sierra, and Cascade Mountains.

Explain what total dissolved solids are, how they are measured, and discuss what levels are acceptable for human drinking water and livestock

Total dissolved solids (TDS) refers to the content of all dissolved substances in a liquid. TDS also includes all material in colloidal suspension, including all organic and inorganic material. The requirement is that the solids must be small enough to pass through a filtration system utilizing a sieve size of two micrometers. The two methods used to measuring total dissolved solids are gravimetry and electrical conductivity. Gravimetric methods are more accurate than conductivity. Gravimetry involves evaporating the liquid solvent to leave a residue which can be weighed with an analytical balance. Electrical conductivity is an estimation of TDS based on a solvents ability to conduct a current. TDS is expressed in units of parts per million (ppm). The largest component of the total dissolved solids is inorganic salt, so TDS is often referred to as salinity. Any water that has a TDS of less than 500 ppm can be consumed by humans. Livestock should not drink water with a TDS of more than 7,100 ppm.

Describe the types of evidence used to build and support a stratigraphic correlation in a field analysis

Tracing a stratigraphic bed or group of rocks from one area to another involves detailed examinations of fossil assemblages, field relationships, depositional environments, and chemical and physical composition. Geologists attempt to use paleontological data, such as index fossils or collections of fossils, in order to date, classify, and compare various strata. In the absence of good index fossils or if contained index fossil do not provide correlation due to poor time resolution, a careful comparison of both the specific and regional geology between correlated areas must be considered. Depositional environments must be correlative and not in opposition to establish a general and valid stratigraphic correlation. Differences in chemical and physical characteristics of stratigraphic units must be explained in establishment of a correlation. Stratigraphic correlation can be based on time or environment such that two very different sedimentary packages can correlate in time. Conversely, two very similar depositional systems may not be time correlative.

Describe the physical lines of evidence used to support a stratigraphic correlation

Tracing a stratigraphic bed or group of rocks from one area to another invovles detailed examinations of field relationships, depositional environments, and chemical and physical composition. Geologists use theories of depositional environments to date, classify, and compare various strata. In the absence of good index fossils, or if contained index fossils do not provide correlation due to poor time resolution, a careful comparison of both the specific and regional geology between correlated areas must be considered. Depositional environments must be correlative and not in opposition to establish a general and valid stratigraphic correlation. Differences in chemical and physical characteristics of stratigraphic units must be explained in establishment of a correlation. Stratigraphic correlation can be based on time or environment such that two very different sedimentary packages can correlate in time. Conversely, two very similar depositional systems may not be time correlative.

Define transmissivity, and discuss how it is used.

Transmissivity is defined as the relative amount of water that can be transmitted horizontally in an aquifer to a pumping well or draw point. The aquifer value for hydraulic conductivity will influence the degree of transmissivity. Transmissivity is also directly dependent upon aquifer thickness. Transmissivity is calculated with the following equation: T = Kb, in which T is transmissivity, K is hydrualic conductivity, and b is the saturated thickness of the aquifer. For a confined aquifer the transmissivity value remains constant because the saturated thickness remains constant. For unconfined aquifers, the thickness is measured from the base of the aquifer to the top of the water table. As the water table in an aquifer can fluctuate, the transmissivity value for unconfined aquifers can vary.

Provide a description for each Unified Soil Classification System (USCS) subdivision of coarse grained soils

Under the Unified Soil Classification System (USCS) coarse grained soils will have more than 50% of total material retained on a No.200 (0.075 mm) sieve. The two subdivisions of coarse grained soils are: gravel, with a requirement that greater than 50% of coarse fraction be retained on No.4 (4.75 mm) sieve; and sand, required to have 50% of its coarse fraction pass a No.4 sieve. Gravel can consist of clean gravel up to gravel with greater than 12% fines. The group divisions of gravel are: well graded gravel, fine to coarse gravel, poorly graded gravel, silty gravel, and clayey gravel. Sand can consist of clean sand up to sand with greater than 12% fines. Sand group subdivisions are: well graded sand, fine to coarse sand, poorly graded sand, silty sand, and clayey sand.

Explain the basic approach for collecting soil samples, and discuss the relationship between sampler characteristics and sample quality.

Undisturbed soil samples can be collected with a Shelby tube or other thin-walled-sampler. The technique involves driving hollow tube penetrators into a column of soil and extracting the sampling tube. A sample is thus obtained and examined with all original characteristics intact including: constituents, grain size distribution, horizons, and structure. The following tests can be performed on an undisturbed soil sample: compressibility, compaction, consolidation, density, and shear strength. Soils may also be collected by grab or gridded sampling techniques or from an excavated test pit. These are disturbed samples and can be tested for constituents and some structural elements. Tests on disturbed soild include: grain size distribution, expansion data, bulk pit wall analyses in many instances. Somewhat limtied but many times sufficient information can be obtained from disturbed soil samples obtained with hand-powered augers or truck-mounted power augers.

Discuss the characateristics and formation of erosional features that are hallmarks of continental glaciation

Unlike alpine glaciers which are restricted to valleys, continental glaciers advance along a wide front and cover large areas. As recently as 12,000 years ago, continental glaciers covered much of the nrothern United States and much if not all of Canada. Some of the features that allow us to recognize areas that were covered by continental glaciation in the past are: end moraines, ablation moraine, large areas covered with glacial till. Also the following geomorphic features and landforms are indicative of continental glaciation: eskers, drumlins, ground moraine, glacial lakes, kettle ponds, and kames. Fluvial features contributable to continental glaciation include: braided outwash streams and outwash plains. Continental glaciation has occurred cyclically over time. Currently there are active continental glaciers in Greenland and Antarctica

Describe what varves are, and how they are useful in sedimentary studies

Varving involves a two-phase sedimentary package or sequence of beds that were deposited in a body of still water. Varves are specifically characterized by yearly cyclical deposition. A varve includes one set or thin pair of graded layers seasonally deposited in a glacial lake or other body of stillwater. Varves are frequently observed associated with glaciation. A glacial varve sequence consists of a lower layer, formed in summer when relatively coarse-grained, light-colored sediment accumulates through the rapid melting of ice; and a thinner layer consisting of very fine-grained dark sediment slowly deposited from suspension in quiet water while the streams are ice bound. Counting and correlation of varves have been used to measure the ages of Pleistocene glacial deposits.

Review how approximate map scale can be assumed, based on what features are included on the map

Very small map scales are needed for large areas such as maps of continents or countries. Map scaling is such that map detail must be forfeited at the expense of coverage area. As the area of interest becomes smaller, such as in state maps, more detail can be presented. An example is a world map that is presented at a scale of 1:30,000,000 and a state map that is prepared at a scale of 1:500,000. Many geologic maps designed to portray the geology of an entire region are prepared at the commonly used scaled of 1:250,000 or 1:100,000, allowing for geologic relationships across an entire area to be seen. As the need for local detail increases to serve societal needs, such as maps of counties or sub-regions, scales typically increase with 1:50,000 or 1:24,000 being common. A very commonly used scale for topographic maps is 1:24,000 as this scale balances required detail with coverage area. With experience, the map user can come to recognize map scale at a glance by learning the content that is typically included on different maps.

Review the characteristics of volcanogenic deposits, and discuss some of the minerals found in them.

Volcanogenic massive sulfide ore deposits are a type of metal sulfide ore deposit, mainly Cu-Zn, which are assocaited with and created by volcanic associated hydrothermal events in submarine environments thermal springs and volcanoes. They are predominantly stratiform accumulations of sulfide minerals that precipitate from ydrothermal fluids on or below the seafloor in a wide range of ancient and modern geological settings. Volcanogenic massive sulfide deposits are distinctive in that ore deposits are formed in close temporal association with submarine volcanism and are formed by hydrothermal circulation and exhalation of sulfides which are independent of seidmentary processes. The temperature will be between 25 and 350 degrees celsius. The rocks formed will contain sulfur, nickel, zinc, lead, copper, iron, tungsten, antimony, and tin. The largest deposits of sulfides are found close to the volcanogenic site, while iron and manganese oxides are typical of the areas farther away from the vent.

Compare and contrast the equations used to determine percentages or ratios relevant to soil phase relationships such as: water content, porosity, void ratio, bulk density, unit weight, and degree of saturation

Water content, porosity, and degree of saturation are typically expressed as a percentage. The equations for water content are: w = Ww/Ws * 100% (weight of water / weight of solids) and w = Mw/Ms * 100% (mass of water / mass of solids). The equation for porosity is: n = Vv/V * 100% (total volume of void spaces / total volume). The equation for degree of saturation is: SR = Vw/Vv * 100% (volume of water/ volume of voids). Void ratio, bulk density, and unit weight are ratios not expressed as a percentage. The equation for void ratio is: e = Vv/Vs (volume of voids / volume of solids). The equation for bulk density is: p = M/V (total mass/ total volume). The equation for unit weight is: y = W/V (total weight/ total volume, usually in pounds/ft^3).

Describe some hypothetical paths that water molecules can take through the hydrologic cycle, including any points where it could be collected

Water moves throughout the Earth through different pathways and at different rates. Evaporation of water from the ocean forms clouds that drift over the land and produce rain. The rainwater flows into lakes, rivers, or aquifers. The water in lakes, rivers, and aquifers either evaporates back to the atmosphere or eventually flows back to the ocean, completing a cycle. A water molecule may be taken up by vegetation and stored, eventually to be released back into the atmosphere in a process known as transpiration. Water that infiltrates the ground may eventually wind up in an aquifer, or it may end up as a constituent of sedimentary rock. Water included in sedimentary rocks or in small fluid inclusions in igneous rocks can be preserved for long periods of time

Explain in detail what causes water hardness

Water that is classified as hard has elevated levels of dissolved metals, usually calcium and magnesium. These ions end up in the water because of the rock content of the surrounding aquifer. Calcium usually enters the water as either calcium carbonate (CaCO3) in the form of limestone and chalk, or calcium sulfate (CaSO4) in the form of evaporite mineral deposits. The predominant source of magnesium is dolomite (CaMg(CO3)2). Hard water does not produce soap lather readily and typically forms a scale in containers in which it has been allowed to evaporate. Total water hardness (including both Ca2+ and Mg2+ ions) is reported in units of parts per million (ppm) or weight/volume (mg/L) of calcium carbonate (CaCO3) in water. Standard hardness tests typically measure only the total concentrations of calcium and magnesium. In some locations, iron, aluminum, and manganese many also be present at elevated levels. Water is considered slightly hard if concentrations are in the 40 to 60 mg/L range and very hard if concentrations exceed 120 mg/L.

Define weathering, and discuss controls on it. Also classify the levels of weathering commonly identified

Weathering is defined as the destructive processes by which geologic materials exposed to atmospheric agents at or near the earth's surface are changed in color, texture, composition, firmness, or form. Weathering is the physical disintegration and chemical decomposition of rock to produce an in-situ mantle of alluvium and colluvium. Most weathering occurs at the surface, but it may take place at considerable depths, as in well jointed rocks that permit easy penetration of atmospheric oxygen and circulating surface waters. Weathering is controlled by mineralogy, rock petrology, rock cementing agents, fracturing, and severity of external processes such as freeze thaw cycles and precipitation levels. Wind is also a great agent of weathering. Weathering is classified as mild, medium, and severe, usually with sub-categories for each.

State what well efficiency is, how it is calculated, and why it is important

Well efficiency is a ratio that compares the theoretical well draw down to the actual well draw down. The following factors may influence the efficency of a well: borehole size, soil conditions, gravel packing, casing characteristics, and screening characteristics. Well efficiency is calculated with the following equation: WE = St/Sa where WE is well efficiency, St is theoretical drawdown, and Sa is the actual drawdown. An inefficient well will require greater drawdown in order to achieve the same output as an efficient well. Well efficiency is sometimes calculated by comparing the measured fraction of laminar head loss to the total head loss. Both of these approaches are flawed theoretically and practically. A more rigorous method of evaluating well efficiency involves comparing the functional relationships between the actual discharge drawdown curve and the curve produced by a properly developed well. Well efficiency is an important parameter in the accuracy of aquifer tests. It is potentially important in spacing and completion depths for commercial and residential water wells.

Discuss the order of orogenic events that formed features in west and west-central North America

West and west-central North America is dominated in the north by the Canadian Shield, in the middle of the continent by the stable continental platform, and in the south by the coastal plain. The Canadian Shield consists of ancient crustal and oceanic rocks of Archaen and early Proterozoic age representing at least 5 episodes of accretion and assembly. In the middle of the continent, deep Precambrian rocks of the continental core are mostly covered by thick sequences of Phanerozoic sedimentary rocks representing the stable continental platform. Tectonic activity is minor to nonexistent with occasional broad domes and basins. The coastal plain extends from Southern Texas through the northern Gulf of Mexico and into the Mississippi embayment. It is a passive continental margin consisting of a deep wedge of clastic sedimentary rocks that was derived from the platform and bounding orogenic belts. The coastal plain formed mostly during the Jurassic and Cretaceous periods. The western portions of North America were formed by numerous orogenic events with associated deformation, faulting, and volcanic activity related to continental convergence.

Discuss the types of landslides that may occur, including falls, topples, spreads, and flows.

When describing landslides, geologists typically used a system of two word descriptors: the first describing the material that is fallen, and the second describing the movement that has occurred. A landslide may contain a number of different materials ranging from soil to rock. A fall is defined as the relatively free falling or precipitous movement of a newly detached segment of bedrock (usually massive, homogeneous, or jointed) of any size from a cliff or other very steep slope; it is the fastest form of mass movement and is most frequent in mountain areas and during spring when there is repeated freezing and thawing of water in cracks in the rock. A topple is an overturning slope movement, with a turning point below the center of gravity of the falling unit. A spread is a simple dry landslide. A flow is defined as a mass movement of unconsolidated material that exhibits a continuity of motion and a plastic or semifluid behavior resembling that of a viscous fluid. Water is usually required for most types of flow movement

Review the terminology and conventions used when representing the attitude of a plane in space, or the bearing and plunge of a line

When describing the orientation of a plane in three dimensions, the two essential components are strike and dip. Strike is defined as the course or bearing of the outcrop of an inclined bed, vein, or fault plane on a level surface. It is the azimuth or bearing of a horizontal line perpendicular to the direction of dip. Dip is defined as the maximum angle at which a bed, stratum, or vein is inclined from the horizontal, measured perpendicular to the strike and in the vertical plane. Collectively, strike and dip constitute bedding attitude. In standard geologic literature, attitude is notated with either a quadrant-based or 360 degree azimuth to display strike direction, followed by the dip azimuth bearing and value. The dip bearing azimuth is required because there are two possible dip directions from any strike line. It is also possible to list only dip and dip direction, assuming that strike will be 90 degrees from the direction of dip.

Describe the time-drawdown method, or Jacob straight-line method, of analyzing aquifer drawdown tests

When only one well is being observed, the time-drawdown method may be preferred to the more complex Theis method. In this method, the drawdown is plotted on the linear side of a semi log paper against time and the linear portion of the data from the last bits of the experiment should be extrapolated backwards to the zero-drawdown axis. Assuming that the cone of depression will not reach a steady state during the first 10 minutes of the experiment, the data from this period can be thrown out. The characteristics of the aquifer may then be calculated with the following equation: s = BQ + CQ^2 where s is drawdown, Q is the pumping rate, B is the aquifer loss coefficient, and C is the well loss coefficient.

Discuss how to map the intersection of a topographic surface with a bedding surface using a topographic map and a given strike and dip

When performing an outcrop pattern problem, the assumption is made that all beds are of uniform thickness and that they have constant strike and dip. Using a topographical map and given strike, the outcrop patterns for inclined beds can be determined graphically or mathematically. Using the graphical method, topographical contours will be drawn along the tip line, in the same direction as the dip. The vertical scale will be drawn perpendicular to the strike. After this is done, the outcrop pattern will be indicated by the intersection of the contours in the dip line. The location of visible outcrop bands will be indicated by lines parallel to the strike lines from those intersections. To use the mathematical method, solve the equation: tan(angle) = rise/run, thereby calculating the spaces between the contour lines on the map

List the components of, and methods used to solve, apparent dip/true dip problems

When the dip of a plane in relation to the horizontal is not measured perpendicular to the strike of that plane, the resulting value is known as apparent dip. The angle between strike and apparent dip direction (B) indicated the relationship between apparent dip angle (a) and dip (q). Apparent dip and true dip problems can be solved with the following four methods: graphic projections, alignment diagram, trigonometric calculation, and the use of an equal area stereonet. The trigonometric method involves right angle geometry and the equation tan a = tan q sin B. The graphic method requires the use of fold-line diagrams in which right triangles are constructed using the dip angle and the apparent dip direction. The equal area stereo net allows the user to calculate dip and apparent dip from a graphical representation of interaction of planes upon a sphere.

Discuss the two graphical methods available to solve a three-point problem for the dip.

When you are given three points with different elevation, the north heading, and the map scale, you can choose one of two methods to graph the information. The three-point problem involves plotting the points on a 2-dimensional map at their precise locations and to scale with each other. A straight line is drawn connecting the deepest and the shallowest points. The point along this line corresponding with the depth of the medium point is determined by drawing structure contours along the line. A line drawn between the medium-depth point and the new point will define strike direction. Dip can then be calculated trigonometrically. With the projection method, a strike line is run from the lowest point in the fold line made in the dip direction. The dip angle is considered to be the angle between the line connecting the projected points and the fold line.

Describe how sand and silt behave differently in response to wind, and classify eolian deposits as either sand- or silt- based

Wind erosion and deposition are controlled by grain size. It requires less wind energy to move silt than sand. Deposits that occur as a result of wind deposition are termed eolian deposits. Wind erosion removes material light enough to be transported and these particles will therefore be moved to another area and re-deposited. This is called deflation. Wind suspended particles may ultimately impact on solid objects causing erosion termed abrasion. Eolian deposits occur as loess and dune sand and include sedimentary structures such as wind-formed ripple marks. Fine-grained, silt sized eolian deposits can occur at any elevation and wind-borne silt can travel long distances. Eolian sand deposits occur closer to their original source due to less transport potential

Discuss the possible losses of groundwater that could be included in a model of ground water inventory

a model of groundwater inventory will necessarily contain a number of different possible losses of groundwater. - groudwater losses are caused directly by location and pumping capacity of specific facilities as well as by aggregate agricultural water use and consumptive use by townships - water can be lost to evaporation from storage facilities and from surface waters - groundwater may also be lost due to uptake by vegetation in a process known as evapotranspiration. the aquifer may seek a bit of water, especially if it has a nonzero hydrualic gradient or is pressurized itself - drawdown from individual wells and infiltration galleries may artificially remove water from an aquifer - leakage from the confining beds that surround an aquifer may decrease groundwater inventory