Geo Quiz 2

To draw syncline and anticline rock diagrams...

**********SEE DIAGRAM**********

To know the order of the layers in a cross section...

**********SEE DIAGRAM**********

What are the three types of map scales?

-Bar Scale -Fractional Scale -Verbal Scale

What are the three motions of a fault?

-Reverse slip -Normal slip -Strike slip

What are the two fold types?

1. Anticline 2. Syncline

Name 5 types of Fold structures

1. Anticline 2. Syncline 3. Monocline 4. Basin 5. Dome

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

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

Name 3 types of Unconformities

1. Disconformity 2. Angular Unconformity 3. Nonconformity

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 three common geologic structures?

1. Folds 2. Faults 3. Unconformities

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 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 four components of a topographic map?

1. Map Scale 2. Map Colors 3. Map Symbols 4. Map Location (North arrow)

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

Name 3 types of faults

1. Normal 2. Reverse 3. Strike Slip

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 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 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.

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

Transform Boundary

1. Two plates pass each other and oceanic crust is not created or destroyed. Best Example: San Andreas Fault

What are the two fold sizes?

1. Wavelength 2. Amplitude

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

Basins

1.) concentric bands of rock at surface 2.) youngest rock in center 3.) cross-sections on sides of basin have the appearance of sync line cross-sections

Domes

1.) concentric bands of rock at surface 2.) oldest rock in centers 3.) cross-sections on sides of dome have the appearance of anticline cross-sections

Plunging Anticlines

1.) oldest beds in the center of folds (both in map/transverse cross-section) 2.) beds decrease in age away from centers 3.) on surface will appear as series of v-shaped bands with the vertex of the "v" pointing in the direction of plunge 4.) oldest beds will appear in the center of the "v"

Anticlines (Non-Plunging)

1.) oldest beds in the center of the folds (both in map/transverse cross-section) 2.) on surface will appear as a series of parallel rock bands elongated on the axis of fold 3.) bands will repeat in opposite order on each side of the axis

Plunging Synclines

1.) youngest beds in center of folds (both in map/transverse cross-section) 2.) beds get older away from centers 3.) on surface will appear as series of v-shaped bands with the vertex of the "v" pointing in the opposite direction of plunge 4.) youngest beds will be in center of "v"

Synclines (Non-Plunging)

1.) youngest beds in the center of the folds (both in map/transverse cross-section) 2.) on surface will appear as a series of parallel rock bands elongated on the axis of fold 3.) bands will repeat in opposite order on each side of the axis

Modified Moracalli Scale

A 12-point scale using Roman numerals developed to evaluate earthquake intensity based on the amount of damage to various structures.

Geologic Map

A 2-D representation of geology on the earth's surface.

Topographic Map

A 2-D representation of the three dimensional surface of the earth.

Fold

A bent or warped stratum or sequence of strata that was originally horizontal, or nearly so, and was subsequently deformed.

Deformation

A change in the shape, position, or orientation of a material, by bending, breaking, or flowing.

Graben

A down-dropped crustal block bounded on either side by a normal fault dipping toward the basin.

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.

Topographic Map

A flat, two-dimensional representation of a 3D land surface. Illustrates the peaks, slopes, hills, depressions, bodies of water ect.

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.

Monocline

A fold whose shape resemble that of a carpet draped over a stair.

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.

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.

fault

A fracture in bedrock along which movement has taken place. (NOT THE SAME AS A FRACTURE)

joint

A fracture or crack in bedrock along which essentially no displacement has occurred.

Thrust Fault

A gently dipping reverse fault; the hanging-wall block moves up relative to the footwall.

Joint

A large and relatively planar fracture in a rock across which there is no relative displacement of the two sides.

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.

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.

geologic map

A map representing the geology of a given area.

geologic map

A map showing the distribution of rock units and structures across a region.

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. 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.

Earthquake

A natural phenomenon that results from sudden release of energy that radiates seismic waves.

Richter Scale

A numerical scale of magnitudes. It defines earthquakes based on the amplitude of the largest ground motion recorded on a seismogram.

axial plane

A plane containing all of the hinge lines of a fold.

geologic cross section

A representation of a portion of Earth in a vertical plane.

thrust fault

A reverse fault in which the dip of the fault plane is at a low angle to horizontal.

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.

reservoir rock

A rock that is sufficiently porous and permeable to store and transmit petroleum.

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.

tensional stress

A stress due to a force pulling away on a body.

compressive stress

A stress due to a force pushing together on a body.

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.

structural dome

A structure in which beds dip away from a central point.

structural basin

A structure in which the beds dip toward a central point.

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 do evenly spaced contour lines represent?

A uniform slope.

angle of dip

A vertical angle measured downward from the horizontal plane to an inclined plane.

Earthquake

A vibration caused by the sudden breaking or frictional sliding rock in the Earth because of a release of energy.

What is a geologic unit?

A volume of a certain rock type of a given range.

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

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)

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

axial plane

An "imaginary" plane dividing the fold in two (one limb on each side, each dipping the opposite direction). You can visualize this by bisecting the fold with a plane using your paper as an example. That surface is the axial plane

anticline

An arched fold in which the rock layers dip away from the axis of the fold. (Makes "A" for anticline)

anticline

An arched fold in which the rock layers usually dip away from the axis of the fold.

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.

Seismograph

An instrument that can record the ground motion from an earthquake.

Magnetic Declination

Angle formed on a map between the direction of true geographic north and magnetic north.

What are the 3 types of unconformities?

Angular unconformity, disconformity, nonconformity

Fracture

Any break or rupture in a rock.

Geologic Structure

Any feature produced by deformation of a rock.

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.

fold

Bend in layered bedrock.

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

How do plates deform?

By folding rocks and displacing rocks along faults.

ductile

Capable of being molded and bent under stress.

strain

Change in size (volume) or shape of a body (or rock unit) in response to stress.

What causes reverse faults?

Compression - causes shortening

brittle

Cracking or rupturing of a body under stress.

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.

Where do body waves travel?

Deep inside the earth.

Latitude

Describes how far North or South an object is (horizontal lines)

Longitude

Desribes how far east or west an object is. (Vertical lines)

Fault

Develops as a result of rocks breaking when stressed, rather than bending.

What is it called when in a strike slip fault, the opposite wall moves right?

Dextral.

Axial Plane

Divides a fold into two limbs that dip in opposite directions.

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.

How do earthquakes occur?

Either naturally or as a result of human activity.

Quadrant Bearing

Expresses direction in degrees East or West of true North or true South

Azimuth Bearing

Expresses direction in degrees between 0 and 360 degrees. ex: North is 0/360, East is 90, South 180, West is 270 degrees.

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

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.

What can you tell about the age of the fault from the rock unit it cuts through?

Has to be at least Mesozoic age.

What age are the rocks?

Holocene

INTRO

INTRO

What is the dip direction in bedding?

It goes from the older rocks to the younger rocks.

joint set

Joints oriented in one direction approximately parallel to one another.

LAB

LAB

Rock divisions/geologic unit

Largest Group - two or more formations Formation - primary unit of lithostratigraphy Member - named lithologic subdivision of a formation Bed - named distinctive layer in a member or formation Smallest

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

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.

What is lateral continuity?

Layers of sediment initially extend laterally in all directions, in other words, they are laterally continuous. 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.

What fault has the younger rocks in the hanging wall?

Normal-slip faults.

When do contour lines merge together?

Only where there is a vertical cliff.

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.

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

Quadrangle

Rectangular portions of Earth's surface found on a topographical map. Exact location is expressed in terms of longitude and latitude.

Mercalli Intensity Scale

Related to the amount of energy it releases, but conveys little information about the effects on people.

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.

Elastic Strain

Rock deformation in which the rock will return to nearly its original size and shape when the stress is removed.

How do you find the difference in arrival time?

S-P

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.

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

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.

Body Waves

Seismic waves that pass through interior of the Earth.

Surface Waves

Seismic waves that travel along Earth's surface.

What causes strike slip faults?

Shear - causes tearing and smearing

What is it called when in a strike slip fault, the opposite wall moves left?

Sinistral.

shear stress

Stress due to forces that tend to cause movement or strain parallel to the direction of the forces.

Shearing

Stress that causes two adjacent parts of a body to slide past one another and parallel to the direction of the forces.

What causes rocks to move?

Stress.

Attitude***

Strike and dip of a feature (bed/rock layer, fault, fold)

What color is the rock unit that USC is located on?

Tan/beige

What causes normal faults?

Tension - causes lengthening

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.

Map Datum

The MSL or USGS quad.

What does a capital letter on a geologic map represent?

The age of the unit.

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.

Foot Wall

The block vertically below the fault.

Contacts

The boundaries between geologic units (different rock layers)

Strain

The change in shape of an object in response to stress.

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.

Brittle Strain

The cracking and fracturing of a material subjected to stress.

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.

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.

What is a contour interval?

The elevation between any two adjacent contour lines on a topographic map.

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.

Stress

The force exerted, in terms of force per unit area, when one body presses upon, pulls upon, or pushes tangentially against another body.

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.

Non Conformity

The interface between igneous rocks are eroded and sedimentary rocks are deposited on top.

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.

What happens when the slope gets steeper on a contour map?

The lines get closer.

Epicenter

The location on the surface directly above the focus.

Focus

The location where a fault slips during an earthquake.

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.

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.

Continental Drift Hypothesis

The movement of plates is described by this hypothesis.

hanging wall

The overlying surface of an inclined fault plane.

Focus

The point from which the EQ's seismic waves originate. Also known as a hypocenter.

Epicenter

The point on the surface of the Earth directly above the focus of the 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.

Seismogram

The record of an earthquake produced by a seismograph.

Seismogram

The record of ground shaking recorded by the seismograph is called a seismogram.

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.

*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.

Seismology

The study of EQ's and seismic waves that move through and around the earth.

Seismology

The study of earthquakes.

Elastic Rebound

The sudden release of stored strain in rocks that results in movement along a fault.

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.

Tensional Stress

The type of stress that tends to pull a body apart.

footwall

The underlying surface of an inclined fault plane.

Elevation

The vertical distance from the datum

Why are contour lines important?

They allow us to show the shape of the land surface on a map.

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.

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.

What do symbols do for us on a geologic map?

They depict the orientation of bedding or layering.

Describe angular unconformity

Tilted layers overlain by horizontal bedding which represents deformation before continued sedimentation

3 maps used in STRUCTURAL geology

Topographic, geologic, block diagrams

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.

Seismic Waves

Waves of energy emitted at the focus of an earthquake.

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)

Where do unconformities form?

Wherever layers were not deposited for a time or eroded away

Fold

Wraps in rocks layers and occur bended upwards, downwards or sideways.

Describe the Law of Superpositioning

Younger sediments are deposited on top of older ones

block diagram

a combination of the geologic map and cross section.

geologic cross section

a diagram showing the geologic features that would be visible by exposing a vertical slice through a part of earth. (the top will usually look like a topographic profile, but folds and bends, as well as faults and rock layers, can be seen, just like a slice of cake with multiple layers.

cleavage

a geometric shape a mineral has when it is broken, or when you move it under the light when it shines

overturned fold

a structural feature in which the fold limb is tilted beyond vertical, which results in both limbs inclined in the same direction, but not at the same angle

*relative age*

age compared to the ages of other rocks

coast

all land near sea, beach and small strip of land

arrangement

and interrelationships of rock units.

hinge line

axis of a rock fold.

islands of hawaii are composed of

basalt igneous rock

footwall

bottom surface of the fault (your feet would be on it while you are hanging from the hanging wall)

arches

bridges of rock left above openings in headlands or stacks by waves

marine terrace

broad gently sloping platform offshore from beach

Describe the Law of Inclusions

clasts, pebbles, fragments, and rocks that are included in other rocks are older than the rock they are in

*extrusions, intrusions, faults and unconformities*

clues to the relative ages of rocks include:_____ ____ _____ and ____

surf

collective group of breakers

Luster

describes the way the mineral reflects light

Contour Interval

difference in elevation between contour lines.

non foliated rocks

do not have layering

estuaries

drowned river mouths from rising seas

what kind of eruption happens on the hawaiian islands

effusive

stacks

erosional remnants of headlands left behind as coast retreats inland

spit

fingerlike ridge of sediment that extends out into open water

two texture types of metamorphic rocks

foliated and non- foliated

Metamorphic rocks

form from other pre-existing rocks which have been buried deep under the earths surface

high grade metamorphic rock

form under extremely high pressures and temperatures

medium grade metamorphic rock

forms closer to the earths surface

fiords

glacially cut valleys flooded by rising sea level

which of the metamorphic rock is high grade

gneiss

foliated rocks

have layering

low grade metamorphic rocks

have very small crystals of the same color. the foliationg can be seen as very thin layers. do not form very deep in surface

Other ways to identify minerals

if feel greasy, bubbles with acid on it, if magnetic or taste salty

*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.

permeability

inter connectedness of the pore spaces within a rock or sediment

coastal straightening

irregular shoreline through wave erosion of headlands and wave deposition in bays

*fault*

is a break in Earth's crust visible because rock layers are "out of alignment"

Opague

is when NO light passes through the mineral

Translucent

is when some light pass through the mineral

berm

landward part of beach, above usual high water line

*unconformity*

layers of rock are missing

Physical properties of a mineral

luster, color, streak color, diaphaneity, cleavage or fracture, and hardness

*intrusion*

magma may push into bodies of rock but not reach the surface ~ when cooled and hardened into rock this forms a(n) ___(blank)______

porosity

measure of the volume of pore space within a rock

angle of dip

measured downward from the horizontal plane to the bedding plane.

Types of Luster

metallic, venturous, Earthy

sediment with the lowest porosity

mix

longshore drift

movement of sediment parallel to shore when waves strike shoreline at an angle

longshore current

moving mass of water parallel to shore

how to calculate discharge

multiplying avg depth by avg velocity and widith

rip currents

narrow currents flow straight out to sea in the surf zone, travel at water surface

wave cut platform

nearly horizontal bench of rock formed beneath surf zone as coast retreats by wave erosion

anticline

oldest rock in middle, asymmetrical

what metamorphic rocks is medium grade

phylitte and schist

two factors which determine whether or not a rock layer will be an aquifer or good source of groundwater is the

porosity and permeability

headlands

promontories

tombolo

rare, bar of sediment connecting former island to mainland

Diaphaneity

refers to how easily light travels through something

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

sediment with the highest porosity

sand

3 grain sizes to identify sediment are

sand pebble mix

If the pore space of ground water is completely filled with water it is

saturated

layer of rocks under the surface is the

saturation zone

what kind of volcaneos are the hawaiian islands

shields

Metallic

shines like metal

Vitreous

shines like plastic or glass

sea cliffs

steep slopes that retreat inland by mass wasting as wave erosion undercuts them

beach face

steepest part of beach, part exposed to wave action

Describe the Law of Lateral Continuity

strata and lava flows extend laterally in all directions until they thin into nothing

beach

strip of sedimet that extends from low water line inland to a cliff or zone of permanent vegetation

*unconformity*

surface where new rock layers meet a much older rock surface beneath them

hanging wall

top surface of fault (you could hang from it)

above the saturated zone, the pore space within the rocks contain only a thin coating of water.

unsaturated zone

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

Grains of metamorphic are either

visible grains to be medium sized or invisible grains to be small sized

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

hot spots are formed

when a plume of magma extends from the mantle to the surface of the earth.

Earthy

when it does NOT reflect light

syncline

youngest rock sin middle