GEO LAB FINAL
esker
(geology) a long winding ridge of post glacial gravel and other sediment
To draw syncline and anticline rock diagrams...
**********SEE DIAGRAM**********
what are two different types of rock that offer good permeability and porosity for aquifers?
- Sandstone and Conglomerate - Fractured, brittle crystalline rocks like limestone, basalt, and granite
What are the three types of map scales?
-Bar Scale -Fractional Scale -Verbal Scale
Reverse fault
-Caused by compression (which causes shortening) -*Thrust fault* -> very low angle reverse fault -Handing wall moves *upward* relative to footwall
Strike slip fault (lateral faults)
-Caused by shear -Horizontal motion
Normal Fault
-Caused by tension (tension causes lengthening) -Handing wall moves *down* relative to footwall -Caused by gravity
Dome
-Circular structure formed when strata warped upward -Upside down bowl -Oldest at the center
Permanent (Streams)
-Flows all year -At or below the water table -Humid or temperate -sufficient rainfall -lower evaporation -Discharge varies seasonally
Angular conformity
-Unconformity between *nonparallel* strata
Step 1: How to draw a topographic profile
1) Draw a line along the topographic map (A-A')
Slower than moving currents
How does the rate of groundwater flow compare with that of moving ocean water or river currents? A. Slower than moving currents B. Can be faster or slower depending on conditions. C. Faster than moving currents D. Same speed as moving currents
Magnitude
How fast the plate is moving
tsunami (seismic sea wave)
Huge ocean wave produced by displacement of the sea floor; also called seismic sea wave.
Floodrisk Analysis
Hydrologic data is used to measure this There are maps regulating areas to manage risks Building in floodplains strictly regulated
phaneritic texture
Igneous rock texture in which minerals are easily visible without magnification.
When do contour lines merge together?
Only where there is a vertical cliff.
Dip angle
Inclination of the water line down from the horizontal plane
Headward Erosion
Intense scoring marks entry into the channels -rapid erosion lengthening the channel further upslope
How is an earthquakes strength measured?
Intensity and magnitude are the two common measures of an earthquakes strength. Intensity is a qualitative measurement, and magnitude is a quantitative measurement.
Star Dunes
Isolated, dunes that don't migrate. Sharp-crested ridges run from each point to a central peak that can be as high as 100 m. These form in locations where the wind blows from multiple directions at different times of the year.
Deserts
Land that is so dry that their biological productivity is too poor to support any type of agriculture.
Drylands
Lands in arid,semi-arid, and dry-sub-humid climates 41% of all land on Earth.
Drainage Evolution
Landscapes evolve over time Stream flow causes most changes EX: -Uplift sets new base level -Stream cuts former surface -Valleys widen, hills erode -Landscape divided to base level
High Discharge
Large cobble & boulders may move
longitudinal dune (seif)
Large, symmetrical ridge of sand parallel to the wind direction.
Bed Load
Larger particles roll, slide, and bounce along
Eon
Largest subdivision of geologic time
What are the 5 laws?
Law of super positioning, Law of original horizontality, law of cross cutting relationships, law of intrusions, law of lateral continuity
a sequence of unconsolidated sediments
Layer 1 of the oceanic crust is
Law of Lateral Continuity
Layers extend in all directions until they thin
What is lateral continuity?
Layers of sediment initially extend laterally in all directions, in other words, they are laterally continuous. Steno's law.
True
Less than 1% of groundwater flow is through underground rive systems. TRUE or FALSE
tillite
Lithified till.
natural levee
Low ridges of flood-deposited sediment formed on either side of a stream channel, which thin away from the channel.
Base Level
Lowest point a stream can erode -ultimate base is sea level -can't erode below -A lake serves as a local (or temporary) base level
lava
Magma that reaches Earth's surface.
ultramafic magma
Magma with a silica content of less than 45%.
mafic magma
Magma with between 45% to 52% silica and proportionately more calcium, iron, and magnesium than intermediate and felsic magma.
felsic magma
Magma with more than 65% silica and considerable sodium, potassium, and aluminum, but little calcium, iron, and magnesium.
Dip has two components
Magnitude and direction
outwash
Material deposited by debris-laden meltwater from a glacier.
outwash
Material deposited by glacier as it melts, similar to deposits. Sorted and separated by the size of its particles.
Erosion Maximization
Maximized during floods -Large water volume -high water velocities -Abundant sediment Streams SCOUR, BREAK, ABRADE, and DISSOLVE
Competence
Maximum size transported
What do GPS measurements do?
Measure the movement of tectonic plates
basal sliding
Movement in which the entire glacier slides along as a single body on its base over the underlying rock.
longshore drift
Movement of sediment parallel to shore when waves strike a shoreline at an angle.
Strike uses 2 quadrants
NE, NW
Dip used Four quadrants
NE, SE, SW, NW
rip current
Narrow currents that flow straight out to sea in the surf zone, returning water seaward that has been pushed ashore by breaking waves.
The plate tectonic model provides a mechanism by which:
1. Continents can move across the surface of the globe 2. Patterns of volcanism can change as plates evolve 3. New oceans grow and sedimentary basins evolve 4. Oceans and sedimentary basins close and produce mountains
Tectonic plates are broken down to which three categories?
1. Divergent 2. Convergent 3. Transform
What are the seven major areas that make up oceanic and continental plates?
1. Eurasian plate 2. North American plate 3. South America plate 4. African plate 5. Pacific plate 6. Australian-Indian plate 7. Antarctic plate
Describe the elastic rebound theory.
1. Faults resist the forces trying to move the pieces apart. 2. As forces build, the fault remains locked and blocks get deformed. 3. Stress is increased. 4. Stress=breaking of the fault. 5. The fault slides past one another.
What do the symbols define?
1. Fold axis 2. Fault planes 3. Dipping beds (tilted layers)
What are the two types of faults?
1. Hanging wall 2. Foot wall
What are the three parts of a fold?
1. Hinge 2. Limbs 3. Core
What three things do colors tell us on a geologic map?
1. It helps us read the map 2. The colors represent a particular rock unit 3. The colors are arranged in a stratigraphic column in which rock units are arranged in boxes from oldest to youngest (bottom to top)
What are the four components of a topographic map?
1. Map Scale 2. Map Colors 3. Map Symbols 4. Map Location (North arrow)
What three things tell us that rocks are deformed?
1. Original Horizontality 2. Geologic age 3. Understanding changes that take place to rock fabrics during deformation
What are the two types of body waves?
1. P-Waves (compressional) 2. S-Waves (shear)
What is the order of arrival in the seismic waves?
1. P-wave 2. S-wave 3. Surface waves
What is permeability controlled by?
1. Porosity a. size of pores: increases permeability b. interconnection of pores: increases permeability - pumice and styrofoam (high porosity but no permeability) 2. Fractures: increases interconnection between pores 3: Fluid viscosity: water less viscous than oil
What are the two types of surface waves?
1. Rayleigh waves 2. Love waves
How do we structurally define rocks?
1. Relative position (dip and strike) 2. Upright vs. overturned
What scales measure earthquakes?
1. Richter Magnitude Scale (size) 2. Mercalli Intensity Scale (damage)
Inclination of surfaces in rocks includes:
1. Rock layers in a fold limb 2. Fault surfaces 3. Rock layers beneath angular unconformity
What are the two deposition principles?
1. Sediments are deposited as layers. 2. A younger layer of sediment is deposited on top of an older layer.
What are three components of unconformities?
1. Stress 2. Erosion 3. Lack of deposition
What two different things measure earthquakes?
1. The magnitude 2. The intensity (damage)
what are two groundwater flow patterns?
- gaining stream - losing stream
Faults and causes
-Breaks along which movement has occurred -Causes: Tension, compression, shear
When velocity of flow decreases
-Competence is reduced and sediment drops out -Sediment grain sizes sorted by water -sands removed from gravel, mud from both -Gravel settles in channels -Sands drop out near channel environments -silts and clays drape flood plains away from channel
What is the theory of plate tectonics?
1. The scientist hypothesized that there was an original gigantic super continent 200 million years ago called "ThePangea" 2. It started by breaking into two continents, Laurasia and Gondwana, separated by teh Tethy's Sea. 3. By the end of the cretaceous, they divided into modern day continents.
Transform Boundary
1. Two plates pass each other and oceanic crust is not created or destroyed. Best Example: San Andreas Fault
What are the four steps to understanding the geologic problems of a region?
1. What is the geologic history 2. What are the geologic sources 3. Where and how are they formed 4. Do they constitute natural hazards
types of unconformities
1. angular unconformity 2. disconformity 3. nonconformity
what are the requirements for artesian water?
1. tilted aquifer at surface to receive water 2. aquitards above and below to confine water under pressure 3. hydrostatic head to force water above its aquifer 4. well or fracture to break aquitard "seal" - water leaks upward
Ice Age Megafloods
11 thousand years ago, ice dams failed -Glacial Lake Missoula -Scarred eastern Washington -Created Channeled Scablands of Washington -barren craggy, stripped rock
Case History: Mississipii and Missouri Rivers
1993- jet stream high altitude winder current drifted southward -Trapped moist, humid air from Gulf. -Air rose and cooled releasing torrents of rain (years worth) -Entered two rivers, flooded -50 dead, 250,000 no drinking water, houses covered silt, 55,000 homes destroyed
Step 3: How to draw a topographic profile
3) Separate piece of paper, draw a horizontal line slightly longer than A-A' -Select a vertical scale according to elevation -Lay the marked paper edge on horizontal line -Place a dot directly above the mark at the elevation it occurs (equal to the vertical scale) -Connect the dots
delta
A body of sediment deposited at the mouth of a river when the river velocity decreases as it flows into a standing body of water.
laccolith
A concordant pluton with a mushroom-like geometry.
barchan
A crescent-shaped dune with the horns of the crescent pointing downwind.
mantle plume
A cylindrical mass of magma rising from the mantle toward the surface; recognized at the surface by a hot spot, an area such as the Hawaiian Islands where volcanism takes place.
Ice cap
A dome-shaped mass of ice and snow that covers a flat plateau, island, or peaks at the summit of a mtn range and flows outward in all directions from the thickest part of the cap.
Graben
A down-dropped crustal block bounded on either side by a normal fault dipping toward the basin.
Recumbent Fold
A fold with a horizontal axial plane.
open fold
A fold with gently dipping limbs.
Symmetrical Fold
A fold with sides showing a mirror image with respect to axial plane.
receding glacier
A glacier with a negative budget, which causes the glacier to grow smaller as its edges melt back.
Syncline
A large downfold, whose limbs are higher than its center.
Anticline
A large upfold of strata, usually 100 M to 300 KM in width, whose limbs are lower than its center.
Tsunami
A large wave along the sea surface triggered by an earthquake or large submarine slump.
end moraine
A low, sinuous ridge of till that develops when the terminus (toe) of a glacier stalls in one position for a while. - form at the end of the glacier
rock flour
A powder of fine fragments of rock produced by glacial abrasion.
stoping
A process in which rising magma detaches and engulfs pieces of the country rock.
reservoir rock
A rock that is sufficiently porous and permeable to store and transmit petroleum.
surface wave
A seismic wave that travels on Earth's surface.
seismograph
A seismometer with a recording device that produces a permanent record of Earth motion.
horn
A sharp peak formed where cirques cut back into a mountain on several sides.
arête
A sharp ridge that separates adjacent glacially carved valleys.
gaining stream
A stream that receives water from the zone of saturation.
compressive stress
A stress due to a force pushing together on a body.
vadose zone
A subsurface zone in which rock openings are generally unsaturated and filled partly with air and partly with water; above the saturated zone.
aphanitic texture
A texture in igneous rocks in which individual mineral grains are too small to be seen without magnification; results from rapid cooling of magma and generally indicates an extrusive origin.
downcutting
A valley-deepening process caused by erosion of a stream bed.
Ice sheet
A vast, pancake-shaped ice mound that covers a large portion of a continent and flows independent of the topographic features beneath it.
angle of dip
A vertical angle measured downward from the horizontal plane to an inclined plane.
What is a geologic unit?
A volume of a certain rock type of a given range.
seismic wave
A wave of energy produced by an earthquake.
artesian well
A well in which water rises above the aquifer.
Discharge
Amount of water flowing in a channel -volume passing a point per unit of time -cubic feet per second -cubic meters per second -Given by a cross-sectional area times flowing velocity -varies seasonally due to precipitation and runoff Example: Niagara Falls (200,000 ft3/sec) Discharge = Q x A
What is an earthquake?
An earthquake is the shaking of the ground cause by the sudden release of energy, usually as a result of faulting.
Moment Magnitude
An earthquake magnitude calculated from the strength of the rock, surface area of the fault rupture, and the amount of rock displacement along the fault.
Drumlin (CONT!)
An elongated mound/ridge of glacial till that accumulated under a glacier and was elongated and streamlined by movement of the glacier. Its long axis is parallel to ice flow. Normally has a blunt end in the direction from which the ice came and a long narrow tail in the direction that the ice was flowing. Mtn/Cont?
Folded Structures (Two types)
Antiforms (up-folds) --> anticlines Synforms (downfolds) --> synclines
Fracture
Any break or rupture in a rock.
Geologic Structure
Any feature produced by deformation of a rock.
Where do most earthquakes occur?
Approximately 80% of all earthquakes occur in the circum-Pacific belt, 15% within the Mediterranean-Asiatic belt, and the remaining 5% mostly in the interiors of plates and along oceanic spreading ridges.
Rapids
Are turbulent water with rough surface -Reflect geologic control -Flow over bed rock steps -Over large clasts -prompt narrowing of a channel -sudden increase in gradient
Drainage Network
Array of linked channels -the networks change overtime
Antecedent Streams
As a mountain uplifts, the stream downcuts just as fast maintaining its original course, cutting across the range.
theory of glacial ages
At times in the past, colder climates prevailed during which significantly more of the land surface of Earth was glaciated than at present.
ventifact
Boulder, cobble, or pebble with flat surfaces caused by the abrasion of wind-blown sand.
wave refraction
Change in direction of waves due to slowing as they enter shallow water.
stalagmite
Cone-shaped mass of dripstone formed on cave floors, generally directly below a stalactite.
Rectangular
Controlled by jointed rocks (limestone, fractures) Example: San Andreas
Barchan Dunes
Crescent shaped dunes... Occur where sand supply is limited and wind direction is fairly constant in one direction. The horns (tips) of these point downwind.
Describe nonconformity
Crystalline rocks (metamorphic or igneous) are overlain by sedimentary rocks
How old are the rocks that the fault is cutting through?
Cutting through Mesozoic age rocks, not cutting through Quaternary age rocks.
associated with volcanic activity
Deep ocean trenches are
Six common patterns
Dendritic, rectangular, radial, centripetal, annular, trellis and deranged
pothole
Depression eroded into the hard rock of a stream bed by the abrasive action of the stream's sediment load.
Cross section
Drawing of a vertical slice through Earth
Crucial for Humans
Drinking, Transport, Waste disposal, recreation, irrigation
speleothem
Dripstone deposit of calcite that precipitate from dripping water in caves.
estuary
Drowned river mouth.
eons
Eras are subdivisions of
lateral erosion
Erosion and undercutting of stream banks caused by a stream swinging from side to side across its valley floor.
Distributaries
Fan of smaller streams
3 stages of water & discharge levels
Normal (water level is below banks), bankfull (water level is even with banks), and flood (water level overflows banks)
What fault has the younger rocks in the hanging wall?
Normal-slip faults.
guyots
Flat-topped seamounts are called ____
Living with Floods
Flood control is expensive and sometimes trivial -Dams on tributaries hold back water from trunk stream -Fake levees and flood walls increase channel volume
flash flood
Flood of very high discharge and short duration; sudden and local in extent.
Calculated Probability
Floodrisk analysis -Discharge plotted vs. Recurrence Levels -Straight line
Causes of Turbulence
Flow obstructions Shear in water -Turbulent eddies scour channel beds
Important Geological Agent
Flowing Water -Eroding, transports, deposits sediments -sculpts landscapes -moves mess from continents to ocean basins
Breaking and Lifting
Force of water can... -break chunks of rock off the channel -lift rocks off the channel bottom
sedimentary
Fossils are generally found in ___ rock
igneous
Fossils are never found in ____ rock
metamorphic
Fossils are rarely found in _____ rock
pyroclastic materials
Fragmental substances, such as ash, that are explosively ejected from a volcano.
Radial
From a point uplift (Mesa, Volcano, etc)
Describe disconformity
Gap in time between parallel strata during periods of non-deposition or whatever was deposited eroded away. Sometimes hard to see due to parallel bedding(strata)
What do unconformities represent?
Gaps in the geologic record
Law of Unconformities
Gaps in the geologic record (Disconformity: parallel; Angular: not parallel; nonconformity; nonsedimentary and sedimentary)
common minerals in metamorphic rocks
Garnet Staurolite Kyanite non-metallic
What are geologic cross sections?
Geologic cross sections are drawings of a vertical slice through the Earth.
What are geologic maps?
Geologic maps show the distribution of rocks at the Earth's surface. Usually, the rocks are divided into mappable units that can be easily recognized and traced across an area. The divisions (contacts between units) are based on color, texture, or rock composition. Geologic maps only show what is exposed at the surface of the Earth.
Rhone Glacier
Had two processes 1.) Flow of glacial ice 2.) Retreat of the end of a glacier through melting or evpaoration
concretion
Hard, rounded mass that develops when a considerable amount of cementing material precipitates locally in a rock, often around an organic nucleus.
What can you tell about the age of the fault from the rock unit it cuts through?
Has to be at least Mesozoic age.
bed load
Heavy or large sediment particles in a stream that travel near or on the stream bed.
Straight Channels
Highest velocity in the center -very few natural straight channels
layers of sediment are generally deposited in a horizontal position AND rock layers that are flat have not been disturbed
What is the Principal of Original Horizontality?
Braided Stream Patterns
When low/high discharge streams become overloaded with sediment, they may form _________ ________ ________. These consist of channels that overlap each other and have linear, underwater sandbars and islands.
Delta
When sediment load accumulates as a triangular or fan-shaped deposit in a lake or ocean, it is called a _______.
Deltas
When stream enters standing water -current slows and loses competence, dropping out sediment -Forms a number of distributaries
Stream Rejuvenation
When streams cut down into landscape that was originally near the stream's base level
along most coastal areas that surround the Atlantic ocean
Where are passive continental margins found?
Where do unconformities form?
Wherever layers were not deposited for a time or eroded away
Thickness of the aquifer
Which of the following does NOT influence the rate at which groundwater flows? A. Hydraulic head B. Thickness of the aquifer C. Permeability D. Hydraulic gradient
Younger, warmer oceanic lithosphere is more buoyant, and angles of descent are small.
Why does oceanic lithosphere subduct?
Principle of Superposition
Younger layers of sediment are deposited on older layers of sediment; thus in a sequence of strata, the oldest layer is at the base
Describe the Law of Superpositioning
Younger sediments are deposited on top of older ones
Foreshore
_____ is an area exposed a low tide.
Wave height
_____ is the difference between the crest and the trough of a wave.
Beach face
_____ is the wet sloping surface that extends from the berm to the shoreline.
Darcy
________'s law is a method to determine the degree of saturation of water at any specified depth.
Capactiy
____________ is the amount of sediment that a stream can carry.
Competence
____________ refers to the largest particle size that a stream can carry.
A broad, gently sloping depositional surface formed at the base of a mountain range in a dry region by the coalescing of several alluvial fans is
a bajada
how do bajada's form
a broad gently sloping depositional surface formed by the coalescing of individual alluvial fans.
what is a marine terrace?
a broad, gently sloping platform that may be exposed at low tide.
alluvial fan
a delta formed where a steep gradient stream abruptly enters a wide, dry plain, creating this
what is a parabolic dune
a dune that is deeply curved and is convex int he downwind direction
what is a transverse dune
a relatively straight, elongate dune oriented perpendicular to the wind direction. associated with a large supply of sand
what is a jetty?
a stone wall that sticks out from the harbor mouth.
strike slip faults
aka lateral faults; caused by shear and involve horizontal motions of rocks
geode
Partly hollow, globelike body found in limestone or other cavernous rock.
Two types of streams
Perennial and intermittent
limb
Portion of a fold shared by an anticline and a syncline.
Angular Unconformity
Pre existing rocks are uplifted and tilted by stress. Then the new sediments deposit horizontally in layers.
Fossil Succession
Principle that a given species appears at a certain time frame and then disappears (goes extinct) at a later time frame
Principle of Original Horizontality
Principle that sediments are deposited in nearly horizontal layers
Uniformitarianism
Principle that the same physical processes observed today are responsible for the formation of ancient geologic features
Correlation
Process of defining the age relationships between the strata at one locality and the strata at another
Cone of depression
Pumping groundwater too fast causes which of the following? A. Artesian well B. Cone of depression C. Change in porosity
The resultant *vector* (velocity vector) is determined using...
Pythagorean Theorem
How do you find the difference in arrival time?
S-P
modified Mercalli scale
Scale expressing intensities of earthquakes (judged on amount of damage done) in Roman numerals ranging from I to XII.
How do we locate the epicenter of an EQ?
Scientists locate EQ's by measuring the time difference between the P and S waves in a seismogram.
Offshore
Seaward of the nearshore is the _____ zone.
suspended load
Sediment in a stream that is light enough in weight to remain lifted indefinitely above the bottom by water turbulence.
Disconformity
Sediment supply is cut off, stopping deposition. There is a gap in the sediment record. Then, new sediment layers are parallel to old layers. The surface between the two groups of layers is the disconformity.
What kind of rocks are they?
Sedimentary
Law of Original Horizontality
Sedimentary layers and lava flows were originally deposited by horizontal sheets
What is superposition?
Sedimentary layers are deposited in a time sequence, with the oldest on the bottom and the youngest at the top. Steno's law.
What is faunal succession?
Sedimentary rock strata contain fossilized flora and fauna which succeed each other vertically in a specific order that can be identified over wide horizontal distances. Smith's law.
True
Since it's unrealistic to build levees & reservoirs that could prevent all conceivable floods, it's sensible to allow some floodplains to revert to wetlands and to create floodways where flooding damage would be minimal. TRUE or FALSE
What is it called when in a strike slip fault, the opposite wall moves left?
Sinistral.
Aftershock
Small earthquake that follows a main shock.
Cirque Glaciers
Small, semicircular to triangular glaciers that form on the sides on mountains.
continental glaciers
So large that they transcend topography
Block diagram
Solid block, geo map on top and cross section on sides 3D model of a portion of crust
A gentle slope is indicated by
Spread out contours
sea cliff
Steep slope that retreats inland by mass wasting as wave erosion undercuts it.
Horn (MTN!)
Steep-sided, pyramid-shaped peak produced by headward erosion of several cirques. Mtn/Cont?
Arroyos/Wadis/Dry Washes
Steep-walled canyons with gravel floors are called ___________.
stream terrace
Steplike landform found above a stream and its flood plain.
Valleys and Cannons
Stratsgraphic variations often yield a stair step profile -Strong rocks yield vertical cliffs -Weak rock produce sloped walls -Geologic processes stack strong and wear rocks -Valleys stowe sediment when base level is reached -Renewed incision creates stream terraces -terraces mark former flood plains V-Shaped Valley-
Stream piracy
Stream Capture -A situation in which headward erosion causes one stream to intersect the coarse of another stream
Sheetwash
Stream flow begins as a moving sheetwash -thin surface layer of water -moves down steep slopes -erodes the substrate
Forming Streams
Stream flow begins as water is added to the surface -Melted snow adds water -snow and rain add water -swamps and puddles collect water on flat land
Erosional Processes
Stream flow doeswork -energy imparted to streamflow is derived from gravity -streams do work by converting potential to kinetic energy
Turbulence
Stream flow is characteristically turbulent -chaotic and erratic -abundant mixing -swirling oddities -high velocity
Problems
Stream runoff also causes problems -flooding destroys lives and properties
Hydrologic Cycle
Stream runoff is a component of this
losing stream
Stream that loses water to the zone of saturation.
Land erosion
Streams are also the single most important natural agent of this (wearing away of the land).
Superposed Streams
Streams carve channels into the flat strata; when they eventually erode down through the unconformity and start to downcut into the folded strate, they maintain their earlier course, ignoring the structure of the folded strata -pre-existing geometry has been laid down on the rock structure
What causes rocks to move?
Stress.
What color is the rock unit that USC is located on?
Tan/beige
A pond at the bottom of a cirque
Tarn
Drainage Reversal
Tectonic Uplift can alter a course of a major river Early Mesozoic, South American drained westward Western uplift raised Andes - now flows east
What is the elastic rebound theory?
That EQ's occur on faults.
What is the rule about contour lines when it comes to elevation?
That every contour line is of the exact same elevation.
zone of ablation
That portion of a glacier in which ice is lost.
zone of accumulation
That portion of a glacier with a perennial snow cover.
a rift valley
The Red Sea is an example of ___
hydraulic action
The ability of water to pick up and move rock and sediment.
What does a capital letter on a geologic map represent?
The age of the unit.
Terminus
The bottom end of the glacier is the ____________. (Think of as a river a ice: This is the RIVER MOUTH)
False
The capacity of a stream or river is the amount of water it carries (discharges). TRUE or FALSE
Strain
The change in shape of an object in response to stress.
What does the theory of plate tectonics explain?
The earth's lithospheric plates move
what is desertification
The encroachment of desert conditions on moister zones along the desert margins, where plant cover and soils are threatened by desiccation.
Mouth
The end of a river valley: where it enters a lake/ocean/dry basin. At this location, the water is dispersed into a wider area, its velocity decreases, and sediment settles to form an alluvial deposit.
Drainage Basin
The entire area of land that is drained by one stream, or an entire stream drainage system.
P-Waves
The first waves to appear on the record and are the fastest moving waves. They travel parallel.
Anticline
The folds with the oldest rocks in their cores.
Syncline
The folds with the youngest rocks in their cores.
major provinces of the ocean floor
The following are ____: Continental margins Deep-ocean basins oceanic ridges
Fossils
The following are types of _____: •The remains of relatively recent organisms— teeth, bones, etc. • Entire animals, flesh included • Given enough time, remains may be petrified (literally "turned into stone"). • Molds and casts • Carbonization
crest (of wave)
The high point of a wave.
Inclined Rock Layer
The layers crop out in V's across valleys. Layers that are inclined in a direction that is a down valley, has a "v" down valley. 0-90 degrees.
headward erosion
The lengthening of a valley in an uphill direction above its original source by gullying, mass wasting, and sheet erosion.
Shoreline
The line that marks the contact between land and sea is called _____
Divides
The linear boundaries that separate one drainage basin from another are called...
elastic limit
The maximum amount of stress that can be applied to a body before it deforms in a permanent way by bending or breaking.
Dip
The maximum angle by which a stratum or other planar feature deviates from the horizontal. The angle is measured in a plane perpendicular to the strike and is measured downward from an imaginary horizontal plane to an inclined plane.
Oxbow Lake
The meander that has been cut off from via a cutoff in a straight reach
Continental Drift Hypothesis
The movement of plates is described by this hypothesis.
hydrologic cycle
The movement of water and water vapor from the sea to the atmosphere, to the land, and back to the sea and atmosphere again.
Epicenter
The point on the surface of the Earth directly above the focus of the earthquake.
Seismogram
The record of ground shaking recorded by the seismograph is called a seismogram.
Mountain Front
The sharp-angled intersection where the steep lower slope of a mountain range meets a pediment/alluvial fan & the slope of the land changes is called the _____________ _______.
Ground Mass, or Matrix describes what?
The smaller and more numerous crystals in a porphyritic rock
stream velocity
The speed at which water in a stream travels.
Cenozoic (recent) Mesozoic (middle) Paleozoic (ancient)
The subdivisions of the Phanerozoic Eon are:
elastic rebound theory
The sudden release of progressively stored strain in rocks results in movement along a fault.
Karst
The term _________ describes a distinctive topography that indicates dissolution of underlying soluble rock, generally limestone.
Tensional Stress
The type of stress that tends to pull a body apart.
Zone of Aeration
The underground zone with water- and air-filled spaces is called the _____ of ____________.
footwall
The underlying surface of an inclined fault plane.
Water table
The upper surface of the zone of saturation is called the _______ _______.
water table
The upper surface of the zone of saturation.
wave height
The vertical distance between the crest (the high point of a wave) and the trough (the low point).
Elevation
The vertical distance from the datum
Floodplains
These develop when alluvium accumulates landward of the river banks, during floods.
Transverse Dunes
These dunes occur where sand supply is greater. They form as long ridges perpendicular to wind direction. The crests are linear to sinuous.
Abyssal plains
These land forms are sites of thick accumulations of sediment, are found in all oceans, and are likely the most level places on earth.
What do depressions look like on contour maps?
They are ellipses with hatched marks.
What do hills look like on a contour map?
They are ellipses without hatched marks.
Love Waves
They are much like S-Waves. Their amplitude decreases with depth and does not reach the core or mantle. They have side to side motion.
What do symbols do for us on a geologic map?
They depict the orientation of bedding or layering.
Overuse of Water
Thirst increases worldwide but water does not Need so much more today
Trellis Stream Drainage Pattern
This stream drainage pattern resembles a vine or climbing rose bush on a trellis. The main stream is long and intersected at nearly right angles by its tributaries. This pattern commonly develops where alternating layers of resistant and nonresistant layers have been tilted and eroded to form a series of parallel ridges and valleys.
Monsoons
Tropical rains on the Indian Subcontinent -Large rains and severe flooding -Many live in floodplain and delta plains -1990, Bangladesh...100,000 dead
Geologic Maps
Two-dimensional map that records the outcrop data using different color & symbols
till
Unsorted and unlayered rock debris carried by a glacier.
Divides
Uplands that separate drainage basins
Main factors that from or shape a river valley
geology, gradient, base level, discharge and load
indirect effects of past glaciation
glacial lakes, pluvial lakes, lowering and rising of sea level, crustal rebound,
fiords
glacially cut valleys flooded by rising sea level
Normal fault
hanging wall moves down
unconfined aquifer
has a water table because it only partly filled with water
meandering
highly sinuous river channel which meanders
fold axis
hinge line
A fold axis can be considered as synonymous with the term
hingeline
erratic
ice-transported boulder that has not been derived from underlying bedrock
angular unconformity
an unconformity between nonparallel strata
disconformity
an unconformity between relatively parallel strata
arrangement
and interrelationships of rock units.
caves (caverns)
are naturally formed, underground chambers
Radial pattern
channel flow outward from central area like wheel spokes "WHEEL SPOKES"
Centripetal pattern
channels converge on a central point like a lake or playa at center of closed basin "REVERSE WHEEL"
block diagram
combo of geologic map and cross section
Alluvium
consists of gravel, sand, silt and clay deposited in floodplains, point bars, channel bars, deltas and alluvial fans.
hornfels
contact metamorphism of sedimentary rocks resulting from intrusions
crevasses
deep cracks in a glacier or in the earth's surface
A streamlined hill composed of glacial drift (till), which indicates the direction of glacier movement, is termed
drumlin
stacks
erosional remnants of headlands left behind as coast retreats inland
Perennial streams
flow continuously throughout the year; blue lines on topo maps
Intermittent streams
flow only at certain times of the year (rainy season, snow melt); 3 blue dots between each line segment)
Sheet flow
flows over fields, streets and sidewalks; several mm or cm deep; downslope in response to gravity
contacts
form lines on geologic maps
What are the characteristics of karst topography?
lack of surface streams, underground caves and numerous surface sinkholes. A major region may cross the area but small surface streams gradually disappear down sinkholes
Jenny lake
lake formed by glacier. Emerged from cascade conyon some 9000 years ago
Low Discharge
large clasts are stranded
foliated
layered banda if minerals aligned in parallel directions
*unconformity*
layers of rock are missing
What is a column?
lengthening stalactites and stalagmites merge
zone of ablation
lower part of the glacier where snow o ice is lost
base level
lowest level to which a stream can theoretically erode
*intrusion*
magma may push into bodies of rock but not reach the surface ~ when cooled and hardened into rock this forms a(n) ___(blank)______
relief and geology
makes characteristic patterns of drainage
formations
mappable rock units
rip currents
narrow currents flow straight out to sea in the surf zone, travel at water surface
levees
natural; higher than the rest of the floodplain where sediment goes only where water barely overflows
wave cut platform
nearly horizontal bench of rock formed beneath surf zone as coast retreats by wave erosion
what shape do particles in waves create?
orbital (circular) particle motions in the water
attitude
orientation of a rock unit or surface
cutback
outer edge of meanders where erosion occurs
younger rocks surrounded by older rocks
outlier
when ice from glacier melts it forms depressions that contain water. What are these called
paternoster lakes
contamination of groundwater
pesticides and herbicides, fertilizers, leached city pollutants, heavy metals, liquid and solid wastes, acid mine drainage, radioactive waste, gasoline, minerals within rocks and soil, pumping wells, saltwater intrusion
Glaciers erode mainly by
plucking and abrasion
Fold axis that are tilted said to
plunge
Head
point of origin of a upland stream or tributary
metamorphic rocks form when...
pre-existing rocks are subjected to temperature, pressure or chemical fluids but not conditions that melt the rock
fossils
preserved remains of ancient plants and animals
migrate
progressive erosion of cutbacks and point bars make meanders do this over time
headlands
promontories
stream terraces
remnants of older floodplains that have been dissected
ablated
removed or taken away by cutting or erosion or melting or evaporation
Scours
running water picks up sediment and moves it
Stream processes
shape earth's surface and cause damage; fluvial processes
What is a groin?
stone wall built to stop long shore erosion of beach
groundwater
the water that lies beneath the surface, filling the pore space between grains in bodies of sediment and clastic sedimentary rock and filling cracks and crevices in all types of rock.
delta
where a stream drops its sediment load that accumulated as a triangular or fan shaped deposit; formed in a lake or ocean
joint set
Joints oriented in one direction approximately parallel to one another.
LAB
LAB
gabbro in a sequence of rocks called an ophiolite complex
Layer 4 of the oceanic crust is
divide
Line dividing one drainage basin from another.
Floodplain
Meandering stream channels cover a small portion Typically has escarpment or bluff along sides and channels over flow to flood plains in entire region
Piedmont Glaciers
Mergers of 2+ valley glaciers at the foot of a mountain range.
Magma
Molten rock material generated within Earth.
How many earthquakes occur per year?
More than 900,000 earthquakes occur per year, with more than 31,000 of those strong enough to be felt.
what processes occur at the beach face?
Most wave energy expended here. Processes= erosion, transport, rounding
traction
Movement by rolling, sliding, or dragging of sediment fragments along a stream bottom.
plastic flow
Movement within a glacier in which the ice is not fractured.
metamorphic or igneous rocks in contact with sedimentary strata
Non-conformity includes ...
Anticlines
Oldest rocks are in middle 'A' shaped
crevasse
Open fissure in a glacier.
Levees
Over time, flooding creates natural _________ that are higher than the rest of the floodplain.
Overtime
Overtime, the nearby channels merge into a large single TRUNK STEAM.
seismogram
Paper record of earth vibration.
Springs
Places where the water flows naturally from the ground (from spaces in the bedrock).
True
Plate tectonics events can produce mountains whose uplift can cause drainage reversal in existing river systems. TRUE or FALSE
berm
Platform of wave-deposited sediment that is flat or slopes slightly landward.
discordant pluton
Pluton with boundaries that cut across the layering in the country rock.
headland
Point of land along a coast.
What is the abbreviation and the formal name of the formation that we are located on?
QIs - Surficial sediments
Now find the North Branch of the San Gabriel Fault. What are the colors, names, and abbreviations of the rock units on either side of the fault?
Qg = light blue = Surficial sediments/landslide Qog = light grey = Surficial sediments Qoa = beige = Surficial sediments Qd = purple = Quartz Diorite
Parent isotope
Radioactive isotope that undergoes decay
1. Dissolved load 2. Suspended load 3. Bed load
Rank the 3 types of sediment load in a stream from smallest to largest Suspended load Bed load Dissolved load
Flash Floods
Rapid water rise with little warning From unusual intense rainfall or dam failure -Typified by rapid moving wall of debris laden water -1889, Johnstown
Map scale
Relation between distance on the map of true distance on Earth's surface
Index fossil
Remains of species that only existed for short periods of geologic time and are diagnostic of a period or epoch
Dam Construction
Resevoirs make irrigation and hydroelectric power Recreation areas Alter ecosystems, barriers to fish, decreased nutrients downstream, removing delta sediment source
Find the Devonshire Fault on the cross-section labeled A-B. Is this fault a normal, reverse, or strike-slip fault?
Reverse fault
What fault has the older rocks in the hanging wall?
Reverse-slip faults.
Recessional Moraine (MTN &CONT)
Ridge of till that forms at terminus of a glacier, behind and generally parallel to the terminal moraine. Formed during a temporary halt in recession of a wasting glacier. Mtn/Cont?
Explain how a geyser works.
Rising water and steam get trapped underground in a narrow crack. Pressure builds until the mixture sprays above the surface and erupts.
Tarn (MTN!)
Small lake in a cirque. A melting cirque glacier may also fill part of the cirque & may be in direct contact w/ or slightly up-slope from this feature.
Kettle Lake/Kettle Hole (MTN/CONT)
Small lake or water-stratified depression (10s to 100s meters wide) in glacial drift, formed by melting of an isolated, detached block of ice left behind by a glacier in retreat or buried in out-wash from a flood caused by the collapse of an ice-damned lakes.
distributary
Small shifting river channel that carries water away from the main river channel and distributes it over a delta's surface.
Coastline
The _____ marks the coast's seaward edge?
Coast
The ______ extends inland from the shore as far as ocean-related features are found.
Nearshore
The _______ zone lies between the low-tide shoreline and the point where waves break at low tide.
Strike
The angle between true north and the horizontal line contained in any planar feature (inclined bed, dike, fault plane, and so forth); also the geographic direction of this horizontal line.
Ductile Strain
The bending and flowing of a material in response to stress. It will not return to its original size and shape when stress is removed.
Hanging Wall
The block vertically above the fault.
permeability
The capacity of a rock to transmit a fluid such as water or petroleum.
volcanic pipe
The conduit connecting the crater of a volcano with an underlying magma chamber.
continental glaciation
The covering of a large region of a continent by a sheet of glacial ice.
Brittle Strain
The cracking and fracturing of a material subjected to stress.
top
The crest of a wave refers to the ___ of the wave
hydrologic cycle
The cycle through which water in the hydrosphere moves; includes such processes as evaporation, precipitation, and surface and groundwater runoff
Relief
The difference in elevation in a specified area
Dip Direction (Strike)
The direction of maximum inclination for a surface measured with respect to true north-in which all points on that line are of equal elevation.
Magnetic Field
The earth has a magnetic polarity due to flow of the molten outer core.
Stress
The force exerted, in terms of force per unit area, when one body presses upon, pulls upon, or pushes tangentially against another body.
a calendar of Earth's history
The geologic time scale is
coastal straightening
The gradual straightening of an irregular shoreline by wave erosion of headlands and wave deposition in bays.
Abrasion
The grinding away of rock by friction and impact during transportation.
What happens in a normal slip fault?
The hanging wall moves down the fault surface and vertically omits rocks layers.
What happens in a reverse slip fault?
The hanging wall moves up the fault surface, and vertically repeats rock layers.
Uplands
The highest elevation of a drainage basin. Also - the smallest valleys of the drainage basin occur here.
wavelength
The horizontal distance between two wave crests (or two troughs).
Non Conformity
The interface between igneous rocks are eroded and sedimentary rocks are deposited on top.
coast
The land near the sea, including the beach and a strip of land inland from the beach.
Epicenter
The location on the surface directly above the focus.
Focus
The location where a fault slips during an earthquake.
Sublimation
The loss of snow/ice by direct change from ice to water vapor.
Ablation
The loss of snow/ice by melting.
Ablation
The loss of the glacial ice or snow by melting, evaporation, or breaking off into icebergs. (Also called wastage).
trough (of wave)
The low point of a wave.
How is the concept of Paleomagnetism proved?
The magnetic polarity of the earth has switched during history, the switches are recorded by magnetic minerals in rocks.
Dip Amount (Dip)
The magnitude of maximum inclination for a surface measured with respect to teh horizontal plane to the top of bed or fault. Does not exceed 90 degrees.
Plate Tectonics
The map of the earth is always changing. The plates are moving and changing in size.
correlation
The matching of rocks of similar ages in different regions is known as ____
hanging wall
The overlying surface of an inclined fault plane.
porosity
The percentage of a rock's volume that is taken up by openings.
crystal settling
The physical separation and concentration of minerals in the lower part of a magma chamber or pluton by crystallization and gravitational settling.
Focus
The point from which the EQ's seismic waves originate. Also known as a hypocenter.
epicenter
The point on Earth's surface directly above the focus of an earthquake.
Seismogram
The record of an earthquake produced by a seismograph.
Hangingwall
The rock or sediment above an inclined fault plane.
Footwall
The rock or sediment below an inclined fault plane.
S-Waves
The second waves to appear and are slower than P-Waves. They travel perpendicular to the motion.
S Waves
The secondary seismic wave, which travels more slowly than the P wave and consists of elastic vibrations transverse to the direction of travel. These waves cannot penetrate a liquid. A type of body wave.
beach face
The section of the beach exposed to wave action.
*Original Horizontality*
The sediment that forms sedimentary rocks is deposited in flat layers.
After Shock
The series of smaller earthquakes that follow a major earthquake.
Fore Shock
The series of smaller earthquakes that precede a major earthquake.
slip face
The steep, downwind slope of a dune; formed from loose, cascading sand that generally keeps the slope at the angle of repose (about 34°).
Gradient
The steepness of a slop - either the slope of a valley wall or the slope of a stream along a selected segment of its channel. Expressed in FEET PER MILE. RISE OVER RUN. Divide the vertical rise/fall btw 2 pts by the horizontal distance btw them.
Seismology
The study of earthquakes.
ground water
The water that lies beneath the ground surface, filling the cracks, crevices, and pore space of rocks.
Rectangular Stream Drainage Pattern
This stream drainage pattern is a network of channels with right-angle bends that form a pattern of interconnected rectangles and squares. This patten often develops over rocks that are fractured/faulted in two main directions. The streams erode channels along the perpendicular fractures/faults.
Deranged Stream Drainage Pattern
This stream drainage pattern is a random pattern of stream channels that seem to have no relationship to underlying rock types or geologic structures.
Describe angular unconformity
Tilted layers overlain by horizontal bedding which represents deformation before continued sedimentation
Half-life
Time is takes for half of a group of radioactive element's isotopes to decay
drainage basin
Total area drained by a stream and its tributaries.
truncated spur
Triangular facet where the lower end of a ridge has been eroded by glacial ice.
True
True of False: Wave energy moves forward, but not the water itself.
True
True or False: The rock containing the inclusion is younger.
Pollution
Turning some rivers into deadly cesspools Raw sewage and drainage from urban areas -Fertilizers, industrial sites, animal waste
Monoclines
Two axial planes that separate two nearly *horizontal limbs* from a single, steeply inclined limb
varve
Two thin layers of sediment, one dark and the other light in color, representing one year's deposition in a lake.
Loess
Un-stratified sheets of clayey silt and silty clay transported beyond the margins of a glacier by wind &/or braided streams. It is compact and able to resist significant erosion when exposed in steep slopes/cliffs.
Subsidence
Vertical sinking of the Earth's surface in a region, relative to a reference plane
Aphanitic Textures
Very fine grain crystals < 1mm, and are too small to see with the naked eye or hand lens.
Hot Spot
Volcanism has been active in this spot for a long time. Hot spots occur if small and long lasting regions (hot spots) exist below plates and provide high heat energy to create volcanoes.
sheetwash
Water flowing down a slope in a layer.
ARE NOT
When aquifers (are/are not) confined, the groundwater establishes a water table just beneath the surface of the land.
Mesas
When bedrock lies roughly horizontal, such erosion creates broad, flat-topped ___________ bounded by cliffs.
Horizontal Rock Layer
When it is cut irregularly due to erosion, it exposes the lower layers. The contacts follow the contour lines. 0 degrees (no dip)
All of the answers are correct
Which of the following is a depositional stream landform? A. Alluvial fan B. Natural levee C. Point bar D. All of the answers are correct
Canyon
Which of the following is an erosional stream landform? A. Alluvial fan B. Point bar C. Canyon
The volume of water passing a point on the stream bank in a given time.
Which of the following refers to stream discharge? A. The volume of water passing a point on the stream bank in a given time. B. The velocity of water passing a point on the stream bank in a given time. C. The volume of sediment being transported by a stream in a given time.
make poor farmland...
Which of the following statements is FALSE? Deltas A. may form where a stream empties into the quiet waters of a lake or the ocean B. are likely to slowly sink and become swampland called a delta plain C. make poor farmland b/c they flood regularly and flooding leaches out the minerals
to prevent deposition
Why are jetties built?
How do you determine the boundary movement of two plate tectonics?
With the plate boundary already drawn, graph the vectors onto the GPS stations using the azimuth (direction) and the velocity (which tells the length); compare the directions and lengths of the vectors
Fold
Wraps in rocks layers and occur bended upwards, downwards or sideways.
what is pediment
a gently sloping surface commonly covered with a veneer of gravel, cut into solid rock of the mountain. develops uphill of a mountain
valley glacier
a glacier that is confined to a valley and flows from a higher to a lower elevation
fiord
a long narrow inlet of the sea between steep cliffs
Gradient
a measure of the steepness of a slope; m=rise/run
continental divide
a narrow strip of land dividing surface waters that drain in opposite directions across the continent; imaginary;
what is a wave built terrace?
a terrace or platform built up by sediments washed offshore. Requires continuous sediment supply
truncated spurs
are ridges that have triangular facets produced by glacial erosion at their lower ends
*extrusions, intrusions, faults and unconformities*
clues to the relative ages of rocks include:_____ ____ _____ and ____
anoxic
depleted of oxygen Not any good fishing
what processes occur at berms?
deposition at high tides
Porphyritic Textures
describes an igneous rock containing two distinct crystal sizes; indicating two cooling periods or the viscosity affected nucleation.
Phenocryst
describes the larger crystals in a porphyritic rock.
Graph Inspection
determines the chance of occurence
what is wave height?
distance between crest and trough
What is Wavelength?
distance between two crests. Determines amount of energy applied to shoreline
mass wasting
downslope movement of Earth materials
what is flowstone?
dripstone drapes walls
estuaries
drowned river mouths from rising seas
playa
dry basin where river water evaporates and precipitates layers of mineral crystals and oxide residues.
disconformity
either an erosion surface or a surface of nondeposition separating rocks whose layers are parallel
lateral moraine
elongate, low mounds of till that form along the sides of a valley glacier - form on the outer edges
drainage basin
entire area drained by one stream or system
what processes occur at marine terraces?
erosion ; ex: wave cut terrace deposition ; ex: wave built terrace
continental glaciation
exists where a large part of a continent is covered by glacial ice
reverse faults
fault caused by compression
normal faults
fault caused by tension
spit
fingerlike ridge of sediment that extends out into open water
Valley glaciers
flow downhill like a viscous liquid
What are aquitards?
impermeable rock - confines and deflects groundwater flow parallel to layering - compartmentalizes aquifers (restricts flow between layers)
*law of superposition*
in horizontal sedimentary rock layers, the oldest layer is at the bottom Each higher layer is younger than the layer below it.
Principle of Superposition
in rocks lying in their original positions, the older rocks are at the bottom and the younger rocks are at the top
dip angle
inclination of the water line, down from the horizontal plane
principle of inclusions
inclusions in a rock is older than the rock containing it (pebbles, cobbles, boulders, xenoliths)
annular pattern
incomplete, concentric rings of streams connected by short radial channels; "RINGS"
beds
individual layers of rock or sediment
older rocks surrounded by younger rocks
inlier
coastal straightening
irregular shoreline through wave erosion of headlands and wave deposition in bays
aquifer
is a body of saturated rock or sediment through which water can move easily high permeable and saturated
*fault*
is a break in Earth's crust visible because rock layers are "out of alignment"
mesa
is a broad flat topped hill bounded by cliffs and capped with a resistant rock layer
well
is a deep hole, generally cylindrical, that is dug or drilled into the ground to penetrate an aquifer within the saturated zone
what is a blowout
is a depression on the land surface caused by wind erosion
glacier
is a large, long-lasting mass of ice, formed on land, that moves under its own weight
ice sheet
is a mass of ice that is not restricted to a valley but covers a large area of land
butte
is a narrow hill of resistant rock with a flat top and very steep sides
spring
is a place where water flows naturally from rock onto the land surface
horn
is a sharp peak that remains after cirques have cut back into a mountain on several sides
cirque
is a steep-sided, half-bowl shaped recess carved into a mountain at the head of a valley carved by a glacier
U-shaped valley
is characteristic of glacial erosion
V-shaped valley
is characteristic of stream erosion
Direction in dip
is the map direction in which the inclined plane slopes downward
perched water table
is the top of a body of groundwater separated from the main water table beneath it by a zone that is not saturated
what is a pillar
it is an erosional remnant of the former land
equilibrium line
marks the highest point at which the glacier's winter snow cover is lost during a melt season
Sediment Load
matter moved by streams
Capacity
maximum load transported
metamorphic grade
maximum pressure and temperature conditions a rock has experienced
gauging stations
measure changes in water level and discharge of a river.
anticlines
oldest rocks are in the middle
When the glacier grows
one of accumulation
why is quartz the most common mineral on many beaches?
quartz is resistant to chemical weathering by water and mechanical weathering by abrasion against other sediments
deranged pattern
random pattern of stream channels with no relationship to rocks or geological structures "RANDOM"
tombolo
rare, bar of sediment connecting former island to mainland
discharge
rate of stream flow at a given time and location; measured in water per unit of time, cubic feet per second
thrust faults
reverse fault that develop at a very low angle and may be very difficult to recognize
how are stalagmites,stalactites, columns, and flowstone formed?
reverse of the equation. Rain that falls on surface of land percolates through and precipitates into stalactites/flowstone or stalagmites if it drips down to the floor of the cave. Columns
baymouth bar
ridge of sediment that cuts a bay off from ocean
barrier islands
ridges of sand that parallel shoreline and extend above sea level
differential erosion
rocks composed of soft and more easily weathered minerals are generally less resistant to erosion and form valleys; of rock.
geologic maps
shows the distribution of rocks at Earth's surface
uplands
smallest valleys in a drainage basin occur at it's highest elevation
beach face
steepest part of beach, part exposed to wave action
outwash plain
streams issuing from a glacier carry the finer components of the till
direct effects of past glaciation
striations and grooves in bedrock from ice flow, till deposition, loess in the midwest, lake formations, drumlins in ontario and new england, moraines, continental glaciation,
movement neither up and down but sideways
strike-slip fault
beach
strip of sedimet that extends from low water line inland to a cliff or zone of permanent vegetation
Mouth
the end of a river valley; of the river where it enters a lake, ocean or dry basin
porosity
the percent of rock or sediment that consists of voids or openings, is a measurement of a rocks ability to hold water
what is deflation
the removal of clay, silt, and sand particles from the land surface by wind
basal sliding
the sliding of the glacier as a single body over the underlying rock
what is a slip face
the steep downwind slope of a dune
saturated zone
the subsurface zone in which all rock openings are filled with water
Texture of igneous rocks describes...
the types of minerals, their size(s), shapes, and arrangement.
water table
the upper surface of the saturated zone
unsaturated zone
the zone where not all of the sediment or rock openings are filled with water
what are sand dunes
they are mounds of loose sand grains piled up by the wind.
gaining stream
they receive water from the saturated zone
lithify
to transform into stone
Water Table
top of saturated zone - GW moves from highs to lows on WT - flow driven by gravity (velocity controlled by slope) - where W.T intersects surfaces -> lakes, streams (wells fill to it)
hanging wall
top surface of the fault
capillary fringe
transition zone with higher moisture content at the base of the unsaturated zone just above the water table
monoclines
two axial planes that seperate two nearly horizontal limbs from a single, more steeply inclined limb
till
unsorted and unlayered rock debris carried or deposited by a glacier
antiforms
upfolds or convex folds
rigid zone
upper part of the glacier, , Upper part of a glacier in which there is no plastic flow.
Describe the principal of fossil succession
using fossils to determine age. Fossils coexist/dissapear from the geologic record in a definite sequential order. Any rock layer containing a group of fossils can be identified and dated in relation to the fossils in other rock layers
cobble that has been polished and abraded by wind action is called a
ventifact
surface water
water contained in places such as lakes, ponds, rivers, streams, and reservoirs
wave refraction
wave hits shallow water at an angle and slows, as more of the wave hits shallow water it becomes parallel to the shore
breaker
wave that has become so steep that crest of wave topples forward
braided stream pattern
when low gradient/high discharge streams become overloaded with sediment, they may form these; with linear, underwater sandbars.
When does water in the hydrologic cycle become groundwater?
when precipitation infiltrates Earth
cone of depression
when water is pumped from a well, the water table is typically drawn down around the well into a depression shaped like an inverted cone
synclines
youngest rocks are in the middle
when the glacier melts
zone of ablation
What are the two fold types?
1. Anticline 2. Syncline
What are the two main types of seismic waves?
1. Body waves 2. Surface waves
What are three things that represent a geologic map?
1. Colors 2. Lines 3. Special Symbols
What are the two lithospheric plates?
1. Continental plates 2. Oceanic plates
Step 2: How to draw a topographic profile
2) Lay a piece of paper along the line (A-A') -Place a mark where each contour intersects edge of paper -Note the elevation
Modified Moracalli Scale
A 12-point scale using Roman numerals developed to evaluate earthquake intensity based on the amount of damage to various structures.
Topographic Map
A 2-D representation of the three dimensional surface of the earth.
sping; well
A ____________ is a natural outlet from which groundwater flows, and a ___________ is a hole drilled or dug to extract groundwater. A. aquifer; aquitard B. spring; well C. hot spring; geyser D. well; spring
tombolo
A bar of marine sediment connecting a former island or stack to the mainland.
Fold
A bent or warped stratum or sequence of strata that was originally horizontal, or nearly so, and was subsequently deformed.
how do bergschrund form
A bergschrund (from the German for mountain cleft) is a crevasse that forms where a moving glacier ice separates from the stagnant ice or firn above.
ground moraine
A blanket of till deposited by a glacier or released as glacier ice melted.
Lateral Moraine (MTN!)
A body of rock fragments at/within the side of a glacier valley where it touches bedrock and scours the rock fragments from the side of the valley. Visible along the sides of the glacier and on its surface in its ablation zone. When the glacier melts, the __________ ____________ will remain as a narrow ridge of till or boulder train on the side of the valley. Mtn/Cont?
Aquifer
A body of saturated rock or sediment through which water can move readily.
Unconformity
A boundary between two different rock sequences representing an interval of time during which new strata were not deposited and/or were eroded
flood plain
A broad strip of land built up by sedimentation on either side of a stream channel.
mesa
A broad, flat-topped hill bounded by cliffs and capped with a resistant rock layer.
marine terrace
A broad, gently sloping platform that may be exposed at low tide.
Bajada
A broad, gently sloping, depositional surface formed at the base of a mountain range in a dry region by the coalescing of individual alluvial fans.
Deformation
A change in the shape, position, or orientation of a material, by bending, breaking, or flowing.
sinkhole
A closed depression found on land surfaces underlain by limestone.
fjord
A coastal inlet that is a glacially carved valley, the base of which is submerged.
P wave
A compressional wave (seismic wave) in which rock vibrates parallel to the direction of wave propagation.
Bajada
A continuous apron of coalescing alluvial fans below a mountain front is a ____________.
oxbow lake
A crescent-shaped lake occupying the abandoned channel of a stream meander that is isolated from the present channel by a meander cutoff and sedimentation.
island arc
A curved line of islands.
parabolic dune
A deeply curved dune in a region of abundant sand. The horns point upwind and are often anchored by vegetation.
kettle
A depression caused by the melting of a stagnant block of ice that was surrounded by sediment.
cone of depression
A depression of the water table formed around a well when water is pumped out; it is shaped like an inverted cone.
blowout
A depression on the land surface caused by wind erosion.
spit
A fingerlike ridge of sediment attached to land but extending out into open water.
viscosity
A fluid's resistance to flow.
overturned fold
A fold in which both limbs dip in the same direction.
Overturned Fold
A fold in which the axial plane is tilted and beds may dip in the same direction on both sides of the axial planes.
plunging fold
A fold in which the hinge line (or axis) is not horizontal.
syncline
A fold in which the layered rock usually dips toward an axis.
isoclinal fold
A fold in which the limbs are parallel to one another.
recumbent fold
A fold overturned to such an extent that the limbs are essentially horizontal.
Overturned fold
A fold tilted so that one limb is upside down
Monocline
A fold whose shape resemble that of a carpet draped over a stair.
Asymmetrical Fold
A fold without a mirror image in respect to axial plane.
stress
A force acting on a body, or rock unit, that tends to change the size or shape of that body, or rock unit. Force per unit area within a body.
Fault
A fracture in bedrock along which movement has taken place.
fault
A fracture in bedrock along which movement has taken place.
joint
A fracture or crack in bedrock along which essentially no displacement has occurred.
well
A hole, generally cylindrical and usually walled or lined with pipe, that is dug or drilled into the ground to penetrate an aquifer below the zone of saturation.
wave-cut platform
A horizontal bench of rock formed beneath the surf zone as a coast retreats because of wave erosion.
pluvial lake
A lake formed during an earlier time of abundant rainfall.
rock-basin lake (tarn)
A lake occupying a depression caused by glacial erosion of bedrock.
Joint
A large and relatively planar fracture in a rock across which there is no relative displacement of the two sides.
Richter Magnitude Scale
A logarithmic scale that measures the increasing amplitude of the ground motion by a factor of 10 increase the magnitude by 1.
Valley Glacier
A long glacier that originates at cirques and flows down stream valleys in the mountains.
drumlin
A long, streamlined hill made of till.
lateral moraine
A low ridgelike pile of till along the side of a glacier.
Mediterranean-Himalayan belt
A major concentration of earthquakes and composite volcanoes that runs through the Mediterranean Sea, crosses the Mideast and the Himalaya, and passes through the East Indies.
geologic map
A map representing the geology of a given area.
Glacier
A mass of ice that has formed through the recrystallization of now, and which moved under the influence of gravity
petrified wood
A material that forms as the organic matter of buried wood is either filled in or replaced by inorganic silica carried in by ground water.
incised meander
A meander that retains its sinuous curves as it cuts vertically downward below the level at which it originally formed.
Cross-cutting relationships
A means of determining the relative age of rock by looking at which rock or structure cuts another; the feature *that has been cut = older*
intensity
A measure of an earthquake's size by its effect on people and buildings.
Intensity
A measure of the degree of earthquake shaking at a given locale based on the amount of damage to buildings and people.
magnitude
A measure of the energy released during an earthquake.
Magnitude
A measure of the energy released during an earthquake. It is determined by taking the common logarithm (base 10) of the largest ground motion observed during the arrival of a P wave or seismic wave and applying a standard correction for distance to the epicenter.
saltation
A mode of transport that carries sediment downcurrent in a series of short leaps or bounces.
medial moraine
A moraine formed when two advancing valley glaciers come together to form a single ice stream, forms in the middle of the glacier - form in the middle
sand dune
A mound of loose sand grains heaped up by the wind.
stream
A moving body of water, confined in a channel and running downhill under the influence of gravity.
butte
A narrow pinnacle of resistant rock with a flat top and very steep sides.
Richter scale
A numerical scale of earthquake magnitudes.
Richter Scale
A numerical scale of magnitudes. It defines earthquakes based on the amplitude of the largest ground motion recorded on a seismogram.
unconfined aquifer
A partially filled aquifer exposed to the land surface and marked by a rising and falling water table.
spring
A place where water flows naturally out of rock onto the land surface.
axial plane
A plane containing all of the hinge lines of a fold.
assimilation
A process whereby magma changes composition as it reacts with country rock.
meander
A pronounced sinuous curve along a stream's course.
rain shadow
A region on the downwind side of mountains that has little or no rain because of the loss of moisture on the upwind side of the mountains.
desert
A region with low precipitation (usually defined as less than 25 cm per year).
transverse dune
A relatively straight, elongate dune oriented perpendicular to the wind.
geologic cross section
A representation of a portion of Earth in a vertical plane.
bar
A ridge of sediment, usually sand or gravel, that has been deposited in the middle or along the banks of a stream by a decrease in stream velocity.
end moraine
A ridge of till piled up along the front edge of a glacier.
superposed stream
A river let down onto a buried geologic structure by erosion of overlying layers.
source rock
A rock containing organic matter that is converted to petroleum by burial and other postdepositional changes.
What is a cross-cutting relationship?
A rock or fault is younger than any rock or fault through which it cuts. Hutton's law.
S wave
A seismic wave propagated by a shearing motion, which causes rock to vibrate perpendicular to the direction of wave propagation.
playa lake
A shallow temporary lake (following a rainstorm) on a flat valley floor in a dry region.
vesicle
A small hole or cavity formed by gas trapped in cooling lava.
stack
A small rock island that is an erosional remnant of a headland left behind as a wave-eroded coast retreats inland.
hanging valley
A smaller valley that terminates abruptly high above a main valley.
cirque
A steep-sided, amphitheater-like hollow carved into a mountain at the head of a glacial valley.
left-lateral fault
A strike-slip fault in which the block seen across the fault appears displaced to the left.
right-lateral fault
A strike-slip fault in which the block seen across the fault appears displaced to the right.
what are rip currents?
A strong, narrow surface current that flows rapidly away from the shore, returning the water carried landward by waves.
structural dome
A structure in which beds dip away from a central point.
sill
A tabular, or sheetlike, concordant pluton.
dike
A tabular, or sheetlike, discordant pluton.
Scoria
A textural name for a rock having so many vesicles that it resembles a sponge.
Concept of Paleomagnetism
A theory that proves that plates are moving-- In the 1950's, scientists used magnetomenter that recognized the magnetic variation across the oceanic floor, this is also known as Magnetic Seafloor Stripes.
what causes tombolos to form?
A tombolo is formed when the refraction patterns of waves around an island cause sand and other materials to be deposited (deposition) between the beach and the island.
earthquake
A trembling or shaking of the ground caused by the sudden release of energy stored in the rocks beneath the surface.
Topographic map
A two-dimensional map that describes the shape of the land to scale: width, length, height of land above sea level
geyser
A type of hot spring that periodically erupts hot water and steam.
Rayleigh wave
A type of surface seismic wave that behaves like a rolling ocean wave and causes the ground to move in an elliptical path.
Love wave
A type of surface seismic wave that causes the ground to move side to side in a horizontal plane perpendicular to the direction the wave is traveling.
What do evenly spaced contour lines represent?
A uniform slope.
playa
A very flat surface underlain by hard, mud-cracked clay.
Earthquake
A vibration caused by the sudden breaking or frictional sliding rock in the Earth because of a release of energy.
perched water table
A water table separated from the main water table beneath it by a zone that is not saturated.
oscillation
A wave of _______ occurs in the open sea in deep water.
confined (artesian) aquifer
An aquifer completely filled with pressurized water and separated from the land surface by a relatively impermeable confining bed, such as shale.
hot spring
An area of volcanic eruptions and high heat flow above a rising mantle plume.
karst topography
An area with many sinkholes and a cave system beneath the land surface and usually lacking a surface stream.
Drainage network
An array of interconnected streams on the landscape is called... A. Tributaries B. Trunk streams C. Drainage network
how do arête form?
An arête is a thin, almost knife-like, ridge of rock which is typically formed when two glaciers erode parallel U-shaped valleys.
moment magnitude
An earthquake magnitude calculated from the strength of the rock, surface area of the fault rupture, and the amount of rock displacement along the fault.
How is the location of an earthquake determined?
An earthquake's epicenter is determined by using time-distance graph of the P- and S-waves to calculate how far away a seismic station is from an earthquake. The greater the difference in arrival times between the two waves, the farther away the seismic station is from the earthquake. By drawing a circle who's radius equals that distance for each of three different seismic stations, seismologists can determine the epicenter of an earthquake.
What are the focus and an epicenter of an earthquake?
An earthquake's focus is the location where rupture whithin Earth's lithosphere occurs and energy is released. The epicenter is the point on Earth's surface directly above the focus. Seismologists recognize three categories of earthquakes based on focal depth: 1)Shallow focus earthquakes with focal depths of less than 70 km, intermediate-focus earthquakes with focal depths between 70 and 300 km, and deep-focus earthquakes with focal depths greater than 300 km.
Isotope
An element that has the same atomic number (# of protons) but a different 3 of neutrons (therefore *different atomic mass*)
volcanic neck
An erosional remnant of the material that solidified in a volcanic pipe.
erratic
An ice-transported boulder that does not derive from bedrock near its present site.
volcanic (extrusive igneous) rock
An igneous rock formed when magma is extruded onto Earth's surface where it cools and crystallizes, or when pyroclastic materials become consolidated.
porphyritic texture
An igneous texture with minerals of markedly different sizes.
Seismograph
An instrument that can record the ground motion from an earthquake.
pluton
An intrusive igneous body that forms when magma cools and crystallizes within the crust, such as a batholith or sill.
equilibrium line
An irregular line marking the highest level to which the winter snow cover on a glacier is lost during a melt season. (Also called snow line.)
stock
An irregularly shaped, discordant pluton with a surface area smaller than 100 km2.
batholith
An irregularly shaped, discordant pluton with at least 100 km2 of surface area.
Plunge
Angle between fold axis and horizontal
What are the 3 types of unconformities?
Angular unconformity, disconformity, nonconformity
Drift
As melting occurs, deposits of rocky gravel, sand, silt, and clay accumulate where there once was ice. These deposits are called _________.
Zone of Accumulation
As snow/ice accumulate in & beneath snowfields of the _______ of __________, they become compacted and highly crystallized under their own weight. (Think of as a river of ice: This is the HEADWATER)
What happens as a result of a breakwater?
Breakwater enables wave refraction which draws sand closer to harbor (like tombolo). As a result, Harbor must be dredged
arch (sea arch)
Bridge of rock left above an opening eroded in a headland by waves.
On cross-section A-A' find the fault below the Cheops Pyramid. This fault formed between the depositions of two rock units. Name these two rock units.
Bright Angel Formation and Dox Formation
plateau
Broad, flat-topped area elevated above the surrounding land and bounded, at least in part, by cliffs.
Faulted
Broken
How do plates deform?
By folding rocks and displacing rocks along faults.
ductile
Capable of being molded and bent under stress.
Limeston
Caves and karst landscapes form most commonly in which type of bedrock? A. Sandstone B. Basalt C. Limestone
Stalagmites
Caves in karst areas often have ___________, stout formations on the cave floor. These form because water dripping on the cave floor precipitate calcite.
Paternoster Lakes (MTN!)
Chain of small lakes in a glacial trough.
strain
Change in size (volume) or shape of a body (or rock unit) in response to stress.
Capacity and Competence
Change with discharge
Meandering Streams
Channels can form intricately looping curves -snake-like curves -travel over broad flat-plains with underlying soft substrate -Region where river has a gentle gradient -Meanders increase volume of river by making longer -Become sinuous with time
Braided Stream
Channels choked by sediments Flow formed around sediment obstructions -DIVERGING- converging flow creates sand and gravel BARS -Bars unstable, sand and gravel cannot stick together so it eventually collapses (no cut in the channel from stream)
Meandering
Channels may become highly sinuous (having many turns/curves), or _____________.
Urbanization
Cities cover large areas with impermeable concrete -Stream water runoff from cities destructive -shorter lag time between rainfall and flood flow -large discharges for shorter duratiosn -Water does not go in ground but floods
A steep slope is indicated by
Close together contours
Trend of the plunge
Compass direction measure in the direction that axis inclined downward
Harry Hess
Considered one of the founding fathers of plate tectonics. Best known for his theories of sea floor spreading
Pegmatitic Texture
Course grain crystals > 1cm
Phaneritic Textures
Course grain crystals; 1-10 mm
brittle
Cracking or rupturing of a body under stress.
Daughter isotope
Decay *product* of radioactive decay
Where do body waves travel?
Deep inside the earth.
The Pacific Ocean
Deep ocean trenches are located in ____
Thalweg
Deepest part of the channel
Fault
Develops as a result of rocks breaking when stressed, rather than bending.
Raging Waters
Devestate people and property During a flood -flow exceeds volume of the channel -Velocity (capacity and competence) increase -Water leaves channel and immerses adjacent land -Moving water and debris scour flood plains -Water slows away from the river
What is it called when in a strike slip fault, the opposite wall moves right?
Dextral.
Total relief
Difference between highest elevation and lowest elevation
Local relief
Difference between two specified points
Magnetic declination
Difference in degrees of true north and magnetic north
Relief
Difference in elevation between two points
How is plate motion described?
Direction of motion *and* velocity
Azimuth
Direction that plate is moving
Three Load Types
Dissolved Load- Suspended Load- Bed load-
Old, young
Dissolved ions are more abundant in ______________ groundwater than in ______________ groundwater.
depth of focus
Distance between the focus and the epicenter of an earthquake.
Benioff zone
Distinct earthquake zone that begins at an oceanic trench and slopes landward and downward into Earth at an angle of about 30° to 60°.
stream gradient
Downhill slope of a stream's bed or the water surface, if the stream is very large.
dendritic pattern
Drainage pattern of a river and its tributaries, which resembles the branches of a tree or veins in a leaf.
Seismograph
EQ's generate seismic waves which can be detected using a sensitive instrument called a seismograph.
What is a lithospheric plate?
Each plate is composed of rigid crust and the uppermost part of the mantle. The most important geologic processes occur at plate boundaries.
Why should we study earthquakes?
Earthquakes are very destructive and cause many deaths and injuries every year. Even if you dont live in an earthquake-prone area, you might someday travel where there is the threat of an earthquake. Knowing what to do before, during and after an earthquake could save your life and prevent serious injury.
How do earthquakes occur?
Either naturally or as a result of human activity.
terminus
End of a glacier
Periods
Eras are divided into
Law of Cross-Cutting
Features that cut across a rock/body of sediment are younger than the body it cuts
FEMA
Federal Emergency Management Agency at www.floodsmart.gov
Geologist study
Geometry of folded and faulted rock layers by field work, drilling programs, and remote geophysical methods
alpine glaciation
Glaciation of a mountainous area.
advancing glacier
Glacier with a positive budget, so that accumulation results in the lower edges being pushed outward and downward.
Toward the Mouth...
Gradient Flattens Higher Discharges Smaller grains typical Channels describe broad meander belts
Near the HEAD WATER source of the stream
Gradient is steep discharge is low sediments coarse channels are straight and rocky
Water Along the Edges
Greater in wider, shallower streams Lesser in narrower, deeper streams
typically moves slowly within the ground through porous rock layers like sandstone
Groundwater A. completely fills the zone of aeration above the water table B. moves underground mainly in underground river channels C. dissolves very porous rock such as obsidian faster than it dissolves limestone D. typically moves slowly within the ground through porous rock layers like sandstone
recharge, discharge
Groundwater flows downward in a (discharge/recharge) area and upward in a (discharge/recharge area).
What is groundwater
Groundwater is the water retained in the pore spaces of rocks below the water table
plutonic (intrusive igneous) rock
Igneous rock that formed from magma intruded into or formed in place within the crust.
Confining Beds / Aquitards
Impermeable bedrock materials prevent the flow of water and are called ____________ ________ or _________. Ex: Layers of clay, mudstone, shale, dense igneous/metamorphic rock.
discharge
In a stream, the volume of water that flows past a given point in a unit of time.
Block
In region's where Earth's crust has been lengthened by tensional forces, mountain ranges and basins develop by _______ faulting.
An inclusion is a piece of rock that is enclosed within another rock.
In relative dating, what is an inclusion?
An unconformity is a break in the rock record produced by erosion and/or nondeposition of rock units.
In terms of relative dating, what is an uncomformity?
Annular Stream Drainage Pattern
In this stream drainage pattern, a set of incomplete, concentric (round) rings of streams are connected by short radial channels. This pattern develops on eroding structural domes and folds that contain alternating folded layers of resistant and nonresistant rock types.
Centripetal Stream Drainage Pattern
In this stream drainage pattern, channels converge on a central point, often a lake or a playa (dry lake bed), at the center of a closed basin.
Radial Stream Drainage Pattern
In this stream drainage pattern, channels flow outwards from a central area, resembling the spokes of a wheel. Water drains from the inside of the pattern, where the "spokes" nearly meet, to the outside of the pattern. This pattern develops on conical hills such as volcanoes and some structural domes.
Buttes
In time, mesas can erode to small, stout, barrel-like columns, called ___________.
Law of Inclusions
Inclusion (a clast found within a rock) is older than the matrix (groundmass)
Beds
Individual layers of rocks/sediment
Wedge-Shaped Bank
Inside edge of channel has slow moving water such that the competence decreaes and sediment accumulates creating a wedge also known as POINT BAR
What is intensity and how is is determined?
Intensity is a subjective, or qualitative, measure of the kind of damage done by an earthquake. Intensity is expressed in values from I to XII in the Modified Mercalli Intensity Scale.
springs
Interconnected fractures that open onto a hillside & an impermeable rock layer intersecting a hillside are both likely locations of A. springs B. artesian wells C. potentiometric surfaces D. cones of depression
concordant pluton
Intrusive igneous body whose boundaries parallel the layering in the country rock.
Dissolved Load
Ions from mineral weathering
What is the dip direction in bedding?
It goes from the older rocks to the younger rocks.
what is the purpose of a jetty?
It is meant to protect the harbor mouth from long shore drift and storm waves. A jetty channelizes + accelerates tidal currents so that sand does not build up in channel. Causes sediment to be trapped upcurrent and eroded downcurrent
To know the order of the layers in a cross section...
**********SEE DIAGRAM**********
Dip
*Angle* between horizontal plane and the inclined layer
Strike
*Direction of a line* formed by the intersection of a horizontal plane and an inclined layer
how do wave refract to produce long shore currents?
- Wave approaches shore obliquely - One end feels seafloor and slows before other end (refracts) - Wave becomes almost parallel to shore
What are three common geologic structures?
1. Folds 2. Faults 3. Unconformities
What are the four rules to drawing a contour line?
1. It separates all points of higher elevation from the lower elevation. The distance between two adjacent lines represents a vertical distance called contour interval. 2. Every fifth line is index, and in bold. 3. The horizontal spacing determines the steepness of the land. 4. Lines never cross.
What are five things that the geology of an area has effects on?
1. Landslides 2. Availability of groundwater in wells 3. Amount of shaking from EQ's 4. Presence of available minerals 5. Landscape shaped to a particular kind of plant growth
What are the seven minor plates that make up the oceanic and continental plates?
1. Nazca plate 2. Scotia plate 3. Arabian plate 4. Philippines plate 5. Juan de Fuca plate 6. Cocos plate 7. Caribbean plate
Divergent Plate Boundary
1. New oceanic crust is formed 2. The plates move apart 3. The process of the plates moving apart is called Sea Floor Spreading Best Example: Mid Atlantic Ridge
what are the tell-tale signs a swimmer uses to identify riip currents in the offshore?
1. Tongue of muddy water 2. Early breaking of waves 3. Subtle water-surface changes (light reflectivity; ripple patterns)
What three pieces are combined to form a geologic map?
1. Topography 2. Rock type 3. Geologic structures
Convergent Plate Boundary
1. Two plates compress 2. One of the plates slides down below and is incorporated into the earth's mantle along a subduction zone 3. Basically, when the plates push together, one subsides and one starts melting, the result is magma rising forming a chain of volcanoes
What are some changes that occur in waves as they approach the shoreline?
1. Velocity decreases 2. Wavelengths decrease 3. wave heights increase 4. crests topple over in surf zone (breakers) -> foamy, turbulent 5. circles flatten and change to back and forth 6. Waves refract along the shoreline
What are the two fold sizes?
1. Wavelength 2. Amplitude
moraine
A body of till either being carried on a glacier or left behind after a glacier has receded.
trellis pattern
A drainage pattern consisting of parallel main streams with short tributaries meeting them at right angles.
radial pattern
A drainage pattern in which streams diverge outward like spokes of a wheel.
rectangular pattern
A drainage pattern in which tributaries of a river change direction and join one another at right angles.
Alluvial fan
A fan-shaped deposit of stream sediment that occurs where a steep-gradient stream abruptly enters a wide, dry plain, creating an _________ _______.
Alluvial Fan
A fan-shaped, delta-like deposit of alluvium made at the mouth of a stream or arroyo, where it enters a graben, level plain, or basin is called a(n) ____________ _________.
Dip-Slip Fault
A fault i which sliding occurs up or down the slope (dip) of the fault.
dip-slip fault
A fault in which movement is parallel to the dip of the fault surface.
strike-slip fault
A fault in which movement is parallel to the strike of the fault surface.
Strike-Slip Fault
A fault in which one block sides horizontally past another (and therefore parallel to the strike line), so there is no relative vertical motion.
normal fault
A fault in which the hanging-wall block moved down relative to the footwall block.
reverse fault
A fault in which the hanging-wall block moved up relative to the footwall block.
Normal Fault
A fault in which the hanging-wall block moves down relative to the footwall block.
Reverse Fault
A fault in which the hanging-wall block moves up relative to the footwall block.
oblique-slip fault
A fault with both strike-slip and dip-slip components.
loess
A fine-grained deposit of wind-blown dust.
pyroclastic (fragmental) texture
A fragmental texture characteristic of igneous rocks composed of pyroclastic materials.
graded stream
A single bed with coarse grains at the bottom of the bed and progressively finer grains toward the top of the bed.
Benioff Zone
A sloping band of seismicity defined by intermediate and deep-focus earthquakes that occur along the downgoing slab of a convergent plate boundary.
kettle
A small depression that forms when a chunk of ice is left in glacial till.
Head river
A stream's point of origin...may be at a spring or at the start of narrow runoff channels developed during rainstorms.
tensional stress
A stress due to a force pulling away on a body.
structural basin
A structure in which the beds dip toward a central point.
breaker
A wave that has become so steep that the crest of the wave topples forward, moving faster than the main body of the wave.
Mapping Geologic Structures
A. A geologist identifies and describes the dominant rock structures in a region 1. Using a limited number of outcrops (sites where bedrock is exposed at the surface) 2. Work is aided by aerial photography, satellite imagery, global positioning systems (GPS), and seismic reflection profiling B. Strike and Dip 1. Sedimentary rocks that are inclined or bent indicate that the layers were deformed following deposition Strike The compass direction of the line produced by the intersection of an inclined rock layer or fault with a horizontal plane Generally expressed as an angle relative to north 2. Dip The angle of inclination of the surface of a rock unit or fault measured from a horizontal plane Includes both an inclination and a direction toward which the rock is inclined
What Causes Rock to Deform?
A. Deformation is a general term that refers to all changes in the shape or position of a rock body in response to stress B. Rock or geologic structures are the features that result from forces generated by the interactions of tectonic plates Includes folds, faults, and joints C. Stress: The Force That Deforms Rocks 1. Stress is the force that deforms rocks When stresses acting on a rock exceed its strength, the rock will deform by flowing, folding, fracturing, or faulting The magnitude is a function of the amount of force applied to a given area 2. Stress applied uniformly in all directions is confining pressure 3. Stress applied unequally in different directions is called differential stress 4. Types of stress Compressional stress squeezes a rock and shortens a rock body Tensional stress pulls apart a rock unit and lengthens it Shear stress produces a motion similar to slippage that occurs between individual playing cards when the top of the stack is moved relative to the bottom D. Strain: A Change in Shape Caused by Stress 1. Strain is the change in shape of a rock caused by differential stress 2. Strained bodies lose their original configuration during deformation
Folds: Rock Structures Formed by Ductile Deformation
A. During crustal deformation, rocks are often bent into a series of wave like undulations called folds B. Characteristics of folds 1. Most folds result from compressional stresses that result in a shortening and thickening of the crust C. Anticline and Synclines 1. Anticlines are upfolded or arched sedimentary layers Oldest strata are in the center 2. Synclines are downfolded or troughs of rock layers Youngest strata are in the center 3. Depending on their orientation, anticlines and synclines can be described as: Symmetrical—the limbs of the fold are mirror images of each other Asymmetrical—the limbs of the fold are not identical Overturned (recumbent)—one or both limbs are tilted beyond vertical Plunging—the axis of the fold penetrates the ground D. Domes and Basins 1. Domes are upwarped circular features Oldest rocks are in the center 2. Basins are downwarped circular features Youngest rocks are in the center E. Monoclines 1. Monoclines are large, steplike folds in otherwise horizontal sedimentary strata As blocks of basement rocks are displaced upward, the ductile sedimentary strata drape over them F. Faults are fractures in rocks, along which displacement has occurred G. Sudden movements along faults are the cause of most earthquakes H. Polished, smooth surfaces, called slickenslides, provide evidence for direction of movement along the fault I. Dip-Slip Faults 1. Dip-slip faults occur when movement is parallel to the inclination The hanging wall is rock surface above the fault The footwall is the rock surface below the fault 2. The vertical displacement along the fault produces long, low cliffs called fault scarps 3. Normal faults are characterized by the hanging wall moving down relative to the footwall Associated with tensional stress as the rocks pull apart 4. Larger scale normal faults are associated with fault-block mountains Example: Basin and Range Province Uplifted blocks are called horsts Down-dropped blocks are called grabens 5. Fault Block Mountains Half-grabens are tilted fault blocks Detachment faults represent the boundary between ductile and brittle rock units 6. Reverse faults are characterized by the hanging wall moving up relative to the footwall Associated with compressional stress as the crust shortens 7. Thrust faults have an angle less than 45o, so the overlying plate moves almost horizontally Most pronounced along convergent plate boundaries Example: Glacier National Park J. Strike-slip faults are characterized by placement that is horizontal and parallel to the strike of the fault 1. Types of strike-slip faults Right-lateral—As you face the fault, the opposite side of the fault moves to the right Left-lateral—As you face the fault, the opposite side of the fault moves to the left K. Strike-Slip Faults 1. Large strike-slip faults that cut through the crust to accommodate plate motion are called transform faults L. Oblique-slip faults exhibit both a strike-slip and a dip-slip movement M. Joints are fractures in a rock where there has been no rock movement 1. Most joints appear in parallel groups
Describe the law of cross cutting
Any feature that cuts across a body of sediment is younger than the body it cuts across. Also includes intrusions.
country rock
Any preexisting rock that has been intruded by a pluton or altered by metamorphism.
igneous rock
Any rock formed by cooling and crystallization of magma or lava or the consolidation of pyroclastic materials.intermediate magma Magma with a silica content between 53% to 65% and an overall composition intermediate between mafic and felsic magma.
Cirque (MTN!)
Bowl-shaped depression on a high mtn slope. Formed by a glacier by the same name melting. Mtn/Cont?
Dendritic
Branching "treelike" pattern due to a uniform material. Formed on flat lying land
surf
Breaking waves.
Stalactites
Caves in karst areas often have ___________, icicle-like masses of chemical limestone made of calcite that hang from cave ceilings. These form because calcite precipitates from water droplets as they drip from the ceiling.
Oxbow lake
Channels may cut new paths during floods. This can cut off the outer edge of a meander, abandoning it to become a crescent-shaped _________ _______.
U-shaped valley
Characteristic cross-profile of a valley carved by glacial erosion.
Processes
Evaporation Transportation Precipitation Infiltration RUNOFF
narrow, deep valleys
Fluvial landscapes that are early in their evolutionary progression have A. broad floodplains B. narrow, deep valleys C. natural levees D. oxbox lakes
Alluvium
Fluvial sediments are called this -Channels are decorated with mud-channel bars -sands build up to t he point bars inside meander beds -muds deposit from channel during floods -streams builds a sediment delta upon entering fan
All igneous rocks are...
Form interlocking crystals and/or glass when magma, or melt cools.
Alfred Wegner
Fossils!! Known best for his theory of continental rift. Also came up with Pangea
What age are the rocks?
Holocene
500 m(^3)/s
If a stream channel has a cross-sectional area of 100m(^2) and the water flows an average of 5 m/s, what is the streams discharge? A. 500 m/s B. 500 m(^2)/s C. 500 m(^3)/s
Yazoo Tributary
If a tributary cannot breach a river's levee, then it will become a _______ ___________ that flows parallel to the river.
Fold axis
Imaginary stratum Folds bend around this imaginary stratum AKA: hinge line Fold axis lies within the axial plane
Niagara Falls
Lake Erie drops 55 m flowing toward Lake Ontario -Dolostone rock is resistant, underlying shale erodes -Blocks unsupported dolostone collapse and fall -Falls continuously erode south to lake erie -Erosion shows deglaciation has formed Niagara Gorge -Diversion of falls reveals huge blocks of rock -Rate of waterfall retreat- present .5 m/yr -Erie will drain when falls reach it
pluvial lakes
Lake formed in a cooler, wetter climate in arid and semi-arid areas. Example - Utah's Great Salt Lake.
tarns
Lakes that form after the glaciers melt, joined together by small streams
Drainage Basins
Land areas that drain into a specific trunk stream -Also known as CATCHMENTS or WATERSHEDS -
What is land subsidence
Land subsidence is a gradual settling or sudden sinking of the Earth's surface due to movement of earth materials
What is the relationship between land subsidence and groundwater?
Land subsidence is the sinking of the ground while groundwater is the water below the water table
alluvial fan
Large fan-shaped pile of sediment that usually forms where a stream's velocity decreases as it emerges from a narrow canyon onto a flat plain at the foot of a mountain range.
Glaciers
Large ice masses that form on land areas that are cold enough and have enough snowfall to sustain them year after year.
circum-Pacific belt
Major belt around the edge of the Pacific Ocean on which most composite volcanoes are located and where many earthquakes occur.
Drainage Networks
Often form geometric patterns -Reflect underlying geology Several common patterns
Living with Floods
People living in floodplains have danger -Flood risks for insurance, home ownders, lenders, gov agencies -
How do EQ's occur?
The earth's outermost surface is broken into rigid plates, known as tectonic plates floating on top of more fluid zone.
Amazon
The river with the greatest discharge in the world is the A. Mississippi B. Nile C. Ob D. Amazon
Seismology
The study of EQ's and seismic waves that move through and around the earth.
Elastic Rebound
The sudden release of stored strain in rocks that results in movement along a fault.
tarns
See rock-basin lake.
seismic sea wave
See tsunami.
body wave
Seismic wave that travels through Earth's interior.
What are seismic waves?
Seismic waves are waves produced by the energy released by an earthquake. They move outward in all directions from an earthquakes focus. The energy release takes the form of body waves, which travel through the solid Earth, and surface waves, which travel along Earth's surface.
Body Waves
Seismic waves that pass through interior of the Earth.
Surface Waves
Seismic waves that travel along Earth's surface.
What is seismology?
Seismology is the study of earthquakes. Earthquakes are recorded on seismographs, and the record of an earthquake is a seismogram.
Arete (MTN!)
Sharp, jagged, knife-edge ridge between 2 cirques or glaciated valleys. Mtn/Cont?
Ground Moraine (MTN & CONT)
Sheetlike layer of till left on the landscape by a receding glacier. Mtn/Cont?
Rill Channels
Sheetwash erosion creates these The rills coalsece, deepen and downcut into CHANNELS
beach
Strip of sediment, usually sand but sometimes pebbles, boulders, or mud, that extends from the low-water line inland to a cliff or zone of permanent vegetation.
floodplain
solid particles accumulate as sedimentary deposits along the river margins
What features represent the intersection of the water table with the ground surface?
springs, lakes
sea cliffs
steep slopes that retreat inland by mass wasting as wave erosion undercuts them
Describe the Law of Lateral Continuity
strata and lava flows extend laterally in all directions until they thin into nothing
artesian well
water is under pressure and rises in wells to a level above the top of the aquifer
Groundwater
water that soaks into the ground
Liquefaction
The transformation of a stable soil into a fluid that is often unable to support buildings or other structures; may be triggered by earthquake vibrations.
lower
The trough of a wave is the ____ part
Stream drainage system
This entire drainage network, from the smallest upland tributaries to the large streams, to the largest river (main stream or main river).
Dendritic Stream Drainage Pattern
This stream drainage pattern resembles the branching of a tree. Water flow is from the branch-like tributaries TO the trunk-like main stream or river. Common where a stream cuts into flat lying layers of rock/sediment or where a stream cuts into homogeneous/crystalline igneous rock or sediment/sand.
Law of Superposition
Undisturbed sequence of strata; oldest layer at the bottom, youngest at the top
is
Water underground (is/is not) subdivided into 3 categories: soil moisture, vadose-zone water, and groundwater.
Drainage Divides
Watersheds exist in a variety of scales -tiny tributaries -continental rivers Large Watersheds -Feed large rivers -section continents Continental divides separate flow to different oceans
translation
Waves of ______ begin form in shallow water when the water depth of is about one-half of the wavelength and the wave begins to "feel bottom."
Seismic Waves
Waves of energy emitted at the focus of an earthquake.
Three main processes of streams
Weathering, transportation and deposition
rectangular pattern
a network of channels with right-angle bends that form an interconnected rectangles & squares pattern. "RIGHT ANGLES"
how do roche moutonnée form
a roche moutonnée (or sheepback) is a rock formation created by the passing of a glacier. The passage of glacier ice over underlying bedrock often results in asymmetric erosional forms as a result of abrasion on the 'stoss' (up-ice) side of the rock and plucking on the 'lee' (down-ice) side.
how do bolson's form
a semiarid, flat-floored desert valley or depression, usually centred on a playa or salt pan and entirely surrounded by hills or mountains. It is a type of basin characteristic of basin-and-range terrain.
headward erosion
a stream channels deepening and eroding of their v-shaped channels uphill through time
losing streams
a stream that loses water to the saturated zone
gaining streams
a stream that receives water from the saturated zone
what is desert pavement
a surface of pebbles and boulders left behind after sand and silt have been blown away
what is a wave cut terrace?
a terrace or platform formed from wave erosion along advancing shoreline
what are giant springs?
areas where water rushes out of the entrance of a cave (down the side of a valley wall)
a steep spine like ridge separating two adjacent glacial valleys is called
arete
ground moraine
continuous layer of till near the edge or underneath a steadily retreating glacier.
what are few streams?
disappearing;few tributaries;poorly integrated
An estuary that occupies a glaciated coastal valley is called a
fjord
yazoo tributary
flows parallel to the river
advancing glaciers
have positive budgets and push outward and downward at their edges
What is an aquifer?
porous, permeable and saturated rock that stores and yields water at high rate - water wells are drilled into them
minerals commonly found in metamorphic rocks
quartz muscovite mica biotite mica calcite
permeability
refers to the capacity of a rock to transmit a fluid such as water or petroleum through pores and fractures
Floodways
regions likely to be flooded -prevent from building -abandon buildings in the areas
trellis pattern
resembles a vine or climbing rose bush, where main stream is long and intersected at nearly right angles by its tributaries "VINES"
dendritic pattern
resembles branching trees "TREE"
Principle of Original Horizontality
sediments are deposited in horizontal layers and non-horizontal layers have been folded or tilted from their original position
principle of original lateral continuity
sediments are deposited in layers that continue laterally in all directions
what is a longitudinal dune
seif: it is a symmetrical ridge of sand that forms parallel to the prevailing wind direction
aretes
seperate adjacent glacially carved valleys
What controls wave height, wavelength, and velocity?
- wind speed - time - distance (fetch): Short choppy waves vs long rollers
Geologic Map
A 2-D representation of geology on the earth's surface.
Medial Moraine (MTN!)
A long narrow body of rock fragments carried in or upon the middle of a valley glacier & parallel to its sides. Formed by the merging of lateral moraines from 2+ merging valley glaciers. When the glacier melts, the __________ __________ will remain as a narrow ridge of till or boulder train in the middle of the valley. Mtn/Cont?
stream channel
A long, narrow depression, shaped and more or less filled by a stream.
esker
A long, sinuous ridge of sediment deposited by glacial meltwater.
travel-time curve
A plot of seismic-wave arrival times against distance.
point bar
A stream bar (see definition) deposited on the inside of a curve in the stream, where the water velocity is low.
lava flow
A stream of magma flowing over Earth's surface.
braided stream
A stream that flows in a network of many interconnected rivulets around numerous bars.
saturated zone
A subsurface zone in which all rock openings are filled with water.
base level
A theoretical downward limit for stream erosion of Earth's surface.
anticline
An arched fold in which the rock layers usually dip away from the axis of the fold.
Blowout
An oval depression in the sand.
Recurrence Interval
Average number of years between successive floods
fold
Bend in layered bedrock.
Folded
Bent
Streams Guide Sediment with Transport
Biggest particles typify steep gradients in head waters Fine particles typify gentler gradients near mouth
iceberg
Block of glacier-derived ice floating in water.
Index contour
Bold line, every fifth contour line
Contacts
Boundaries between geologic units
ridges
Broad, linear swells along divergent plate boundaries are called
epochs
Periods are divided into
Map Datum
The MSL or USGS quad.
dissolved load
The portion of the total sediment load in a stream that is carried in solution.
Discharge
The rate of stream flow at a given time & location. Measured in cubic feet per second.
What is a beach face?
The section of a beach exposed to wave action. Flows oceanward
Synclines
Youngest rocks are in middle 'U' shaped
dips inward
basin
Dips outward
dome
synforms
downfolds or concave folds
non-foliated
no layering, so they become recrustallized into larger aggregates
Vesicles
occur when gas bubbles become trapped in cooling lava, and such rocks have a vesicular texture. ex. pumice has so many vesicles it floats in water.
hanging wall moves up
reverse fault
Dip direction
Always perpendicular to the line of a strike
beach
An accumulation of sediment found along the landward margin of an ocean or lake is called a _____
What do you need to know to calculate the *velocity vector of moving plate tectonics*?
1) The latitude (north-south) velocity 2) The longitude (east-west) velocity
Two frequently used methods for designating a location on map
1) longitude and latitude 2) Public land survey (PLS)
what are two rock types that are good for aquitards?
-shale -mudstone -unfractured crystalline rocks
Karst Features
-sink holes -circular ponds -solution valleys -few streams and tributaries
what is a gaining stream?
-water table slopes toward stream - gains water (groundwater discharge: ground water is feeding the stream) - stream discharge increases downstream -stream at level of water table
what causes a cone of depression?
-wells fill up by penetrating water table -water table slopes inward - caused by continuous pumping of water and unsaturated zone sloping towards the water table
Trellis
Alternating resistant and weak rocks
Which one of the following is not associated with an unconfined aquifer?
. aquitard at top and base
New Orleans
...
Describe the erosion done by groundwater?
1 Running water on the surface of the earth erodes the land. Groundwater also can cause erosion under the surface. As water flows through the soil, acid is formed. This acid can cause minerals to be dissolved. 2 Minerals that are carried in groundwater can also be deposited in other places. This cycle of erosion and deposition can cause underground caves to form. This happens especially in areas where there is limestone below the surface.
Ephemeral (Streams)
-Not flow all year -Above the water table -Dry climates -low rainfall -high evaporation -flow mostly during rare flash floods
Base level changes cause stream...
-Raising base level results in an increase in deposition -Lowering base level accelerates erosion -A ledge of resistant rock may define local base level -Erosive forces act to slowly remove the resistant layers -Act to restore longitudinal profile
What are the three motions of a fault?
-Reverse slip -Normal slip -Strike slip
Abrasion
-Sediment grains in flow "sandblast" rocks -bedrocks exposed in channels often polished and smooth -Gravel surrounding turbulent eddies drills holes in the bedrock -bowl shaped depresions - POTHOLES -Unusual and intricate sculptes
Nonconformity
-Unconformity between *sedimentary rock* and *non*-sedimentary rock
Disconformity
-Unconformity between relatively *parallel* strata -Could be caused by a time gap, erosion, etc.
what is drawdown?
-amount of depression in cone -depends on withdrawal rate -other wells dry up -discharge must be balanced by recharge
blueschist minerals
-formed in high pressure & low temperature metamorphism -blue in color -foliated
Suspended Load
Fined particles (silt and clay) in flow
INTRO
INTRO
Stream flow
Rivers of water flowing down channels
Elastic Strain
Rock deformation in which the rock will return to nearly its original size and shape when the stress is removed.
Bedrock
Rock that is exposed at the land surface or underlies the soil.
Ventifact
Rocks that have scoop shaped of flat surfaces abraded by sandblasting.
Alluvial Fans
Sediments rapidly dropped near stream source -coarsest material found near stream source -sediments fine and thing away from source Sediments create conical, fan shaped stretches Forms at base of a mountain front
Limbs
Sides of the fold
moraine
a body of non stratified till
Mountain
(Continental/Mountain) glaciation is characterized by cirque glaciers, valley glaciers, and piedmont glaciers.
Continental
(Continental/Mountain) glaciation is characterized by kettle lakes and kettle holes, drumlins, and eskers.
What is a losing stream?
- water table slopes away from stream - loses water (ground water recharge:water is going back into groundwater) - stream discharge decreases downstream
Zone of Aeration/Unsaturated Zone
- zone above Water table - pores partly filled with water - water held (suspended) on grain contacts (surface tension) - sourced by rainfaill - water moves vertically down
Deformed TrilobiteHow Do Rocks Deform?
A. Elastic, Brittle, and Ductile Deformation 1. Elastic deformation: The rock returns to nearly its original size and shape when the stress is removed 2. Once the elastic limit (strength) of a rock is surpassed, it either bends (ductile deformation) or breaks (brittle deformation)
The intersection of the water table with the ground surface may occur at
A. a lake B. a spring C. a swamp D. a stream
Numerical age
Age of a rock/structure as specified in number of years (AKA: "absolute age")
What are the two major types of surface waves?
Rayleigh waves (R-waves) and Love waves (L-waves) move along or just below Earth's surface. R-waves are the slower of the two and behave like water waves in that the individual particles of material move in an elliptical path within a vertical plane oriented in the direction of wave movement. L-wave motion is similar to S-wave motion, but the individual particles of material move back and forth in a horizontal plane perpendicular to the direction of wave travel.
Datum
Reference plane
Bench marks (BM)
Reference points of elevation
Mercalli Intensity Scale
Related to the amount of energy it releases, but conveys little information about the effects on people.
barrier island
Ridge of sand paralleling the shoreline and extending above sea level.
Terminal Moraine (MTN & CONT)
Ridge of till that formed along the leading edge of the farthest advance of a glacier. Mtn/Cont?
drumlins
a long, canoe shaped hill made of till and shaped by an advancing glacier
what is permeability?
ability to transmit a fluid - controls flow rates - requires porosity
point bar
accumulation along the inner edge of meanders
*relative age*
age compared to the ages of other rocks
coast
all land near sea, beach and small strip of land
Mount desert island
along the coast of maine exhibits a number of elongate lakes
High elevation Glaciers
alpine glaciers
dip direction
always perpendicular to the line of strike
angular unconformity
an erosion surface separating rocks whose layers are not parallel; layers above and below meet at an angle
nonconformity
an erosion surface separating sedimentary rocks from older plutonic or massive metamorphic rocks (rocks that are crystalline and not layered)
A deeply curved dune with its horns pointing downwind is a
barchan dune
trend
bearing measured in the direction that the axis is inclined downward
geology
bedrock geology over which the stream flows affects the stream's ability to find or erode is course
footwall
bottom surface of the fault
Dissolution
mineral matter dissolves in water
Floods damage
more human property in the US than any other natural hazard.
ice budget
more water the more ice develops, the less water the more the ice begins to melt away
longshore drift
movement of sediment parallel to shore when waves strike shoreline at an angle
plastic flow
movement that occurs within the glacier due to the plastic or "deformable" nature of the ice itself
longshore current
moving mass of water parallel to shore
texture
the arrangement of minerals in the rock, wether foliated or nonfoliated
What happens if sand supply from long shore drift exceeds erosion?
the beach widens (and vice versa)
metamorphism
the changea in the solid state to pre-exiating rock deep within the eart
strike
the compass bearing (direction) of a line formed by the intersection of a horizontal plane and an inclined layer of rock, fault, fracture or other surface
Zone of Saturation/Saturated Zone
- below water table - water fills all pores and fractures (an underground ocean) - water can move sideways (not just vertically) *feeds lakes and streams (kept filled between rains) - recharged from unsaturated zone
how are caves formed?
- caves form along fractures and beds - solition (acidic rain: CaCO3 + H2CO3-> Ca++ + 2HCO3) widens fracture into rooms - water table drops (rooms drain) - dripstone forms by re-precipitation of calcite
Longitudinal Changes
-Changes character with distance -In profile, gradient describes a concave-up curve
Basin
-Circular structure formed when strata warped downward -Bowl -Youngest at the center
Thrust Fault
A gently dipping reverse fault; the hanging-wall block moves up relative to the footwall.
pediment
A gently sloping erosional surface cut into the solid rock of a mountain range in a dry region; usually covered with a thin veneer of gravel.
valley glacier
A glacier confined to a valley. The ice flows from a higher to a lower elevation.
ice sheet
A glacier covering a large area (more than 50,000 square kilometers) of land.
ice cap
A glacier covering a relatively small area of land but not restricted to a valley.
what is the purpose of a groin?
A groin is supposed to trap drifting sand and widen beach; however it cuts off supply to downcurrent area and causes that area to erode and narrow.
glacier
A large, long-lasting mass of ice, formed on land by the compaction and recrystallization of snow, which moves because of its own weight.
longshore current
A moving mass of water that develops parallel to a shoreline.
Earthquake
A natural phenomenon that results from sudden release of energy that radiates seismic waves.
meander cutoff
A new, shorter channel across the narrow neck of a meander.
magma chamber
A reservoir of magma within Earth's upper mantle or lower crust.
thrust fault
A reverse fault in which the dip of the fault plane is at a low angle to horizontal.
baymouth bar
A ridge of sediment that cuts a bay off from the ocean.
Bowen's reaction series
A series of minerals that form in a specific sequence in cooling magma or lava; originally proposed to explain the origin of intermediate and felsic magma from mafic magma.
How Do Rocks Deform?
A. Factors That Affect Rock Strength 1. Temperature: Higher temperature rocks deform by ductile deformation whereas cooler rocks deform by brittle deformation 2. Confining pressure: Confining pressure squeezes rocks, making them stronger and harder to break 3. Rock type: Crystalline igneous rocks generally experience brittle deformation, whereas sedimentary and metamorphic rocks with zones of weakness generally experience ductile deformation 4. Time: Forces applied over a long period of time generally result in ductile deformation B. Ductile Versus Brittle Deformation and the Resulting Rock Structures 1. Most rocks exhibit brittle behavior in the upper 10 kilometers of the crust Joints are cracks in the rocks resulting from the rock being stretched and pulled apart Faults are fractures in the rocks where rocks on one side of the fault are displaced relative to the rocks on the other side of the fault 2. Folds are evidence that rocks can bend without breaking Usually the result of deformation in high-temperature and pressure environments
Human activities that tamper with, or alter, the groundwater system may result in
A. chemical changes B. saltwater invasion C. subsidence D. change in the water table level
what is recharge?
Addition of water to ground, which raises the water table -natural recharge = * rainfall * desert rivers : "losing streams" lose discharge in SW USA -artificial recharge *dam up rivers to increase infiltration area (raises water table) *increases water's residence time (time it spend in one same position) and surface area on ground
Relative age
Age of one geologic feature with respect to another
Till
All rock material picked up, transported, and deposited by a glacier
Runoff
All the water that falls on the landscape and eventually ends up in streams is called: A. Sheetwash B. Runoff C. Watershed D. Groundwater
what is artesian water?
Confined water under pressure in which the pressure pushes the water above its aquifer -not all artesian wells flow water
Cutbanks
Erosion occurs on the outer edge of meanders, which are called _________.
Accumulation / Ablation
Glacial ice formed in the zone of ___________ flows and slides downhill in to the zone of ___________, where it melts or sublimes faster than new ice can form.
How do glaciers move?
Glacial migration, ie. the movement of glaciers, is a phenomenon usually caused by gravity. The "long profile" is similar to that of a river, except that the path formed by the glacier is more rounded than that of a river. Glaciers move as the bottom layer of ice melts and the subsequent water allows the glacier to move more smoothly, lubricating the action. As the glacier moves, it will normally remove portions of the ground it moves past or over, as they become attached to the constantly freezing and thawing outer layers. This process is constant, although it is commonly more active in the day, when more of the ice melts, allowing faster and better lubricated motion.
downward, upward
Groundwater flows (downward/upward) in a recharge area and (downward/upward) in a discharge area.
How are sedimentary and volcanic rocks deposited
Horizontal Layers. They can be bend by folding and broken by faulting
stalactite
Iciclelike pendant of dripstone formed on cave ceilings.
suspended load
Identify the FALSE statement. Streams cause erosion by A. suspended load B. scouring C. breaking & lifting D. abrasion
pillow lavas
Layer 2 of the oceanic consists of
numerous interconnected dikes (sheet dikes)
Layer 3 of the oceanic crust contains
What is original horizontality?
Layers of sediment are originally deposited horizontally. The principle is important to the analysis of folded and tilted strata. Steno's law.
hinge line
Line about which a fold appears to be hinged. Line of maximum curvature of a folded surface.
Contour Lines
Lines drawn on a map connecting points of equal elevation.
hot spot
Localized zone of melting below the lithosphere that probably overlies a mantle plume.
Esker
Long, narrow, sinuous ridge of stratified drift deposited by meltwater streams flowing under glacial ice or in tunnels within the glacial ice.
Curved Channels
Maximum velocity travels the outside curve -outside curve is preferentially scoured and deepened -Deepest part of the channels is the THALWEG -flow around curve follows a spiral path
Velocity
Not uniform in all areas of channels Friction shows water along the edges creates greater friction
Longitudinal (Linear) Dunes
Occur in some modern deserts where sand is abundant. Crosswinds merge to form high, elongated dunes. The crests are generally straight to slightly sinuous.
Sources of Earth's Water
Oceans - 97.2 % Other- 2.8 % -Glaciers - 2.15% -Ground Water- .62% -Freshwater Lakes- .009% -Saline Lake/Inland Seas- .008% -Stream Channels- .0001% -Atmosphere-.001%
What are the two types of body curves?
P-waves, or primary waves, are the fastest seismic waves and travel through all materials. They are compressional in nature; that is, the material in which they travel is expanded and compressed as the waves move through it. S-waves, or secondary waves, are somewhat slower than P-waves and can travel only through solids. They are shear waves because they move material perpendicular to the direction of travel.
Shearing
Stress that causes two adjacent parts of a body to slide past one another and parallel to the direction of the forces.
Waterfalls
Streams cascade or free fall Energy causes a PLUNGE POOL at base Erosion initiates collapse of overlying rocks -temporary base levels
alluvial fans
Streams come down out of steep areas onto much flatter land, lose velocity, and drop material in wedge-shaped structures called A. point banks B. alluvial fans C. levees D. deltas
Disappearing Streams
Streams that terminate abruptly by seeping into the ground are called...
shear stress
Stress due to forces that tend to cause movement or strain parallel to the direction of the forces.
Sinkholes
Surface depressions formed by the collapse of caves or other large underground void spaces are called...
How should a swimmer escape from a rip current?
Swimming parallel to beach
6000 ft(^3)/s
The 100 feet wide and 10 feet deep river flows at an average velocity of 6 ft/s. Its discharge is: A. 4,800 ft(^3)/s B. 240 ft(^3)/s C. 6000 ft(^3)/s D. 660 ft(^3)/s
Load
The amount of material that is transported by a stream.
drainage pattern
The arrangement in map view of a river and its tributaries.
Foot Wall
The block vertically below the fault.
sulfur
The colors in hot springs are due to presence of thermophyllic lichens that metabolize (iron/sulfur/limestone) in the water.
direction of dip
The compass direction in which the angle of dip is measured.
strike
The compass direction of a line formed by the intersection of an inclined plane (such as a bedding plane) with a horizontal plane.
What is the elastic rebound theory, and what does it explain about earthquakes?
The elastic rebound theory is an explanation for how energy is released during earthquakes. As rocks on opposite sides of a fault are subjected to force, they accumulate energy and slowly deform until their internal strength is exceeded. at that time, a sudden movement occurs along the fault, releasing the accumulated energy, and the rocks snap back to their original undeformed shape.
What is a contour interval?
The elevation between any two adjacent contour lines on a topographic map.
True
The jet stream was a key contributing factor to Mississippi Rive flooding in 1993 because it trapped warm, moist Gulf of Mexico air over the central United States. TRUE or FALSE
What happens when the slope gets steeper on a contour map?
The lines get closer.
terminus
The lower edge of a glacier.
drawdown
The lowering of the water table near a pumped well.
Base level
The lowest elevation to which a stream channel can erode is defined as its A. Competence B. Base level C. Stream gradient D. Longitudinal profile
Base Level
The lowest level to which a stream can erode. Ex: Base level is achieved where a stream enters a lake/ocean. At this point, the erosional power of the stream is zero and depositional processes occur.
Hadean
The oldest eon is
focus
The point within Earth from which seismic waves originate in an earthquake.
P Waves
The primary or fastest wave traveling away from a seismic event through the solid rock and consisting of a train of compressions and dilations of the material.
magma mixing
The process whereby magmas of different composition mix together to yield a modified version of the parent magmas.
Berm
The relatively flat platform composed of sand and marked by a change in slope at the seaward edge is called a _____
deflation
The removal of clay, silt, and sand particles from the land surface by wind.
What are the two processes of glacial erosion
The two main processes that lead to glacial erosion are plucking and abrasion. Plucking is the process by which a glacier picks off rocks as it blocks over the land. The rock fragments freeze to the bottom of the glacier, gouging and scratching the bedrock as the glacier advances in the process of abrasion.
Aeration / Saturation
The water-logged zone below the zone of ___________ is called the zone of ___________.
Parabolic Dunes
These dunes have horn pointing upwind. Always form adjacent to blowouts.
Bachanoid Dunes
These form when barchan dunes are numerous and the horns of adjacent barchan dunes merge into transverse ridges. The crests of these dunes are chains of short crescent-shaped segments that are the crests of individual barchan dunes.
Why are contour lines important?
They allow us to show the shape of the land surface on a map.
Rayleigh Waves
They are much like ocean waves. The passage is elliptical. They travel on the surface of the earth and causes major damage.
Vertical Rock Layer
They crop out across the topography. They run straight across all kinds of topography without deviation. 90 degrees.
rigid zone
Upper part of a glacier in which there is no plastic flow.
solution
Usually slow but effective process of weathering and erosion in which rocks are dissolved by water.
Solution Valleys
Valley-like depression formed by: 1. A linear series of sinkholes. 2. Collapse of the roof of a linear cave.
Contour interval
Vertical difference in elevation between adjacent contour lines
Cone of depression
Water being withdrawn from a well in an unconfined aquifer faster than it can be replenished can cause a cone-shaped depressions in the water table. This is known as a ________ of ___________.
Artesian Wells
Water in a well that rises naturally from the confined aquifer to the potentiometric surface.
Runoff
Water in motion over the land surface
Groundwater
Water in the saturated zone is called _____________.
Cut Bank
Water on the outside of the channel flows fastest and erosion eats away at the channel walls creating a cut bank.
isolated volcanic peaks
What are 'seamounts'?
rapid burial and possession of hard parts (skeleton, shell)
What are the conditions favoring fossil formation?
"visible life" 540 mya
What does "Phanerozoic" mean and when did it begin?
tilted rocks are overlain by flat-lying rocks
What is angular unconformity?
strata on either side of the unconformity are parallel
What is disconformity?
Backwash from the ocean
What is not a source of water in streams? A. Runoff from surrounding lands B. Direct rainfall C. Backwash from the ocean D. Groundwater discharge
In an undeformed sequence of sedimentary rocks (or layered igneous rocks), the oldest rocks are on the bottm
What is the Law of Superposition?
Younger features cut across older features.
What is the Principal of Cross-Cutting Relationships?
228 m(^3)/s
What is the discharge of a stream with a cross sectional area of 12.0 m (^2) and an average velocity of 19.0 m/s?
An eon
What is the greatest expanse of time in the geologic time scale?
capillary fringe
What is the name of the thin zone at the top of the water table, which may "suck" water molecules upward a few millimeters or cm into the unsaturated zone? A. zone of replenishment B. root zone C. capillary fringe D. zone of transition
Index fossil
What kind of fossil is geographically widespread and is limited to a short span of geologic time?
calcium and magnesium
What makes "hard water" hard? A. Calcium & magnesium B. Minerals C. Sediment D. Bacteria
Saltation
Which of the following is NOT a mechanism of erosion by running water? A. Scouring B. Abrasion C. Breaking & lifting D. Dissolution E. Saltation
Flooding
Which of the following is NOT a threat to the long-term sustainability of a river? A. Pollution B. Flooding C. Excess water use D. Urbanization
A, B, & C
Which of these are sources of groundwater contamination? Select all that apply. A. Petroleum B. Dissolved Ions C. Sewage D. Recharge
A and C
Which of these can cause hot spring formation? Select all possible causes A. Places where volcanoes are active or were recently active B. Places with high water tables and low land surfaces C. Groundwater rises to the surface from great depths D. Groundwater exists in a perched aquifer
developed its shape b/c the ocean current there was stronger than the river current
Which statement is FALSE? The Mississippi River Delta A. consists of several distinct lobes B. is the product of several avulsions C. developed its shape b/c the ocean current there was stronger than the river current D. is a bird's-foot delta E. is the site of the city of New Orleans
Backshore
______ is landward of the high-tide shoreline.
Permeability
_____________ is a measure of how well the pores are connected. A. Porosity B. Permeability
Porosity
______________ is a measure of the amount of the substance composed of pores. A. Porosity B. Permeability
oxbow lake
a crescent shaped lake formed when new river paths cut off the outer edge of a meander
what is a barchan
a crescent-shaped dune that has a steep slip face on the inward or concave side. associated with a limited supply of sand
What are loess
a deposit of wind blown silt and clay composed of unweathered, angular grains of quartz, feldspar, and other minerals weakly cemented by calcite
what are stalagmites?
a deposit, usually of calcium carbonate, more or less resembling an inverted stalactite, formed on the floor of a cave or the like by the dripping of percolating calcareous water.
what are stalactites?
a deposit, usually of calcium carbonate, shaped like an icicle, hanging from the roof of a cave or the like, and formed by the dripping of percolating calcareous water.
geologic cross sections
a drawing of a vertical slice through Earth, with the material in front of it
Strike of an incline plane
a) Specify North b) Angle of departure from north(0 to 90 degrees) c) Direction of departure from north (east or west).
what is a ventifact
any rock that has been smoothed or pitted by the wind which has sand and ice particles in it
load
amount of material that is transported by a stream
relative geologic age
an estimate of the numerical age; a relative sequence of geologic age based on one layer compared to another
nonconformity
an unconformity between sedimentary rock/sediment and nonsedimentary rocks
The resultant *azimuth* is determined using...
angle = tan(-1) ((longitude velocity)/(latitude velocity))
dip
angle between a horizontal plane and the inclined stratum, fault, or fracture
plunge
angle between the fold axis and horizontal
principle of cross-cutting relations
any geologic feature that cuts through another feature is younger than the one it cuts
faults
breaks along which movement has occured
arches
bridges of rock left above openings in headlands or stacks by waves
what are plateaus
broad flat topped areas elevated above the surrounding land and bounded at least in part by cliffs
marine terrace
broad gently sloping platform offshore from beach
how do playa lake's form
can be formed from runoff water and are very shallow and temporary
what are sinkholes?
cave roofs collapse and create sinkholes and depressions
what makes karst topography?
cave roofs collapsing
principle of fossil assemblages
characteristic groups of fossil organisms define unique geologic ages
The head of a glaciated valley is commonly marked by a steep arcuate wall and an amphitheater like feature called a what
cirque
Describe the Law of Inclusions
clasts, pebbles, fragments, and rocks that are included in other rocks are older than the rock they are in
what are solution valleys?
coalescing sinkholes
surf
collective group of breakers
metamorphic conditiona can occur in
collision zones subduction zones adjacent to igneous intrusions deep in the surface
confined aquifer
completely filled with water under pressure and is usually separated from the surface by a relatively impermeable confining bed, or aquitard, such as shale
rock flour
composed largely of very fine particles of unaltered minerals
common geologic events
deposition of sedimentary units, extrusion or intrusion of igneous rocks, metamorphism, folding, faulting, uplift, erosion
what happens to the discharge in deserts?
deserts lose their discharge to the water table thereby recharging the water table
overturned fold
fold that is tilted so that one limb is upside down
limbs
folds normally have two sides
type of metamorphism
foliated:regional non-foliated:contact blueschist minerals: blueschist/subduction
Glaciation during the Pleistocene has had a profound effect on many aspects of our physical environment. Which one of the following is not a result of the Pleistocene glaciation?
formation of the Tulsa Mountains
principle of fossil succession
fossil organisms succeed one another in time in a definite and recognizable order; fossils in a sedimentary unit define a specific unique interval of geologic time
alpine glaciation
found in mountainous regions
receding glaciers
glaciers with negative budgets grow smaller and their edges melt back
how can land subsidence be triggered by decreasing the ground water level?
groundwater withdrawal can lead to compaction of rocks and subsidence of the land surface
Where several cirques surround a mountain peak
horn
what are springs?
water erupts onto surface at changes in permeability -where water table intersects surface -flow rates change with climate
berm
landward part of beach, above usual high water line
icebergs
large masses of ice detached from glaciers and floating in the sea. About 90 percent of an iceberg's mass is below the surface of the water
domes and basins
large, somewhat circular structures formed when strata are warped upward like an upside down bowl; strata is oldest at the center of a dome and youngest at the center of a basin
Annual Probability
likelihood that a flood of a given size or larger will happen at a specified locality during any given year
A fold axis bisects a fold into what
limbs
divides
linear boundaries that separate one drainage basin from another; Continental Divide or Great Divide in Rockies; dashed lines
how do spits form?
long shore drift continues to move sediments parallel to the beach and extends the spit
how do baymouth bars form?
long shore drift moves sediments parallel to the beach, blocking off bays which causes the bays to become fresh water bays or brackish.
what are the characteristics of depositional coasts?
look up
what are the characteristics of drowned coasts?
look up
what are the characteristics of errosional coasts?
look up
what is a cone of depression?
look up
protolith
parent rock- determines the resultant metamorphic rock -may be sedimentary, igneous or lower grade metamorphic rocks
what is porosity?
percent of void space (pores and fractures) and rock's storage volume for water -Determined by: * stacking arrangement * sorting: if poorly sorted, small grains fill larger pores * cement: fills pores * compaction: if rocks are more compacted, porosity is decreased
Describe the formation of petrified wood and geodes.
petrified wood: develops when porous buried wood is either filled in or replaced by inorganic silica carried in by groundwater geodes: partly hollow globe-shaped bodies found in some limestone's and locally in other rocks. formed by groundwater
What is a berm?
platform of wave-deposited sediment that is flat or slopes slightly landward.
what is a breakwater?
structure built to protect from waves.it is built parallel to shore. It also creates an artificial harbor for coastlines without harbors.
structural geology
study of how geologic units are arranged when first formed and how they are deformed afterward
*unconformity*
surface where new rock layers meet a much older rock surface beneath them
Groundwater motions driven by gravity
water flows from "highs" towards "lows" on water table
uplift and erosion to form present day surface
the last event in all relative geologic age sequences
Strike
the map direction of the line formed by the intersection of an inclined plane and the horizontal
what is the relationship between porosity and permeability?
the more porosity a rock has the more permeability. sediments are more porous and permeable than rocks because of the amount of cementation and compaction. Rocks are more cemented and compacted
zone of accumulation
the part of the glacier that has a perennial snow cover