Geology Test 3

Front 1

When do waves begin to "feel bottom"?

Back 1

When water depth is equal to 1/2 the wavelength

Front 2

T/F Jetties help keep harbor entrances open by interrupting long shore drift of sand

Back 2

True

Front 3

Which would characterize a depositional coast?

Back 3

Barrier islands

Front 4

The most recent interglacial period of time (a time of warmer climate) known as the Halocene epoch began around?

Back 4

10,000 years ago

Front 5

T/F Strain is defined as a force per unit area?

Back 5

False

Front 6

Rock flower that is picked up transported and redeposited by the wind may form?

Back 6

Loess

Front 7

T/F A desert is generally defined as a region that receives less than 45cm of rainfall a year?

Back 7

False

Front 8

T/F Base level for a stream can never be above or below sea level?

Back 8

False

Front 9

T/F Shale usually makes an aquifer

Back 9

False

Front 10

While enjoying the surf off ocean city Maryland, you notice that you are moving farther down the beach from your blanket and umbrella (parallel to the shoreline), and you realize that?

Back 10

You are being transported by a longshore current

Front 11

T/F Kearst topography is characterized by dissolution features such as sinkholes, disappearing streams, and cave systems?

Back 11

True

Front 12

T/F A glacial valley drowned by rising sea levels is called an estuary?

Back 12

False

Front 13

What is longshore drift?

Back 13

Arise from waves striking at an angle to the beach causes the development of features such as spits and baymouth bars

Front 14

The path a water particle makes asa a wave passes in deep water is best described as?

Back 14

Orbital

Front 15

T/F A narrow deep stream channel with a smooth bed will result in a lower velocity than a wide, shallow channel with a rough bed?

Back 15

False

Front 16

A confined aquifer is separated from the surface by?

Back 16

A relatively permeable layer of rock or sediment

Front 17

Ground water flows from?

Back 17

Areas of high hydraulic head to areas of low hydraulic head

Front 18

T/F Wind- generated waves provide most of the energy that shapes and modifies shorelines

Back 18

True

Front 19

T/F Wave refraction bends wave crests and brings them closer to parallel to the shoreline?

Back 19

True

Front 20

Porosity is?

Back 20

The percentage of a rocks volume that consists of voids or open spaces

Front 21

Which is not a type of moraine?

Back 21

Braided

Front 22

T/F The largest expanse of continental ice at the present time is in Greenland?

Back 22

False

Front 23

the budget of a glacier

Back 23

difference between the glaciers annual gain of snow and ice and its annual loss

Front 24

a drainage pattern that resembles branches of a tree and forms in regions of uniform lithology

Back 24

dendritic

Front 25

(T/F) the water table marks the upper boundary of the saturated zone

Back 25

true

Front 26

an uplifted or emergent coast is characterized by?

Back 26

exposed marine terraces

Front 27

what is the discharge if a section of stream channel is 30ft wide with an average depth of 5ft and is flowing at 10ft per second

Back 27

1500cfs

Front 28

(T/F) deltas are bodies of sediment that form at the mouths of streams as they flow into larger bodies of water because the velocity of the water drops and deposition occurs

Back 28

true

Front 29

most of the desert regions of the earth are located?

Back 29

near 30 degrees N latitude and 30 degrees S latitude

Front 30

a fingerlike ridge of sediment that extends out into open water and is produced by longshore drift

Back 30

spit

Front 31

(T/F) cares more commonly form in granite

Back 31

false

Front 32

(T/F) saltation refers to the process of cobble or boulder-sized particles rolling or sliding along a stream bed

Back 32

false

Front 33

Glacially carved valleys are usually ____ shaped in cross-section

Back 33

U

Front 34

percentage of rock or sediment that consists of voids or open spaces

Back 34

porosity

Front 35

capacity of a rock to transmit a fluid through pores and fractures

Back 35

permeability

Front 36

some water in pore space, but pore spaces are not filled

Back 36

unsaturated zone (vadose)

Front 37

transition zone between unsaturated and saturated zones

Back 37

capillary fringe

Front 38

all pore spaces are filled with water

Back 38

saturated zone

Front 39

saturated zone separated from main water table beneath it

Back 39

perched water tables

Front 40

equal to the elevation of drop plus the water pressure on the drop

Back 40

hydraulic head

Front 41

difference in head between two points divided by the distance between the two points

Back 41

hydraulic gradient

Front 42

potential movement of ground water and its effect on flow lines

Back 42

flow of ground water is perpendicular to lines of equal hydraulic head (equipotential lines) in the down gradient direction (follows the slope of the water table)

Front 43

type of aquifer; has water table, is only partly filled with water

Back 43

unconfined

Front 44

type of aquifer; completely filled with water has aquitard at top, which separates it from surface

Back 44

confined

Front 45

results when water is pumped faster than recharge can refill the region near the well

Back 45

drawdown and cones of depression

Front 46

the addition of new water to the saturated zone

Back 46

recharge

Front 47

form in some confined aquifer systems

Back 47

artesian wells

Front 48

streams that gain water from the saturated zone

Back 48

graining

Front 49

streams that lose water to the saturated zone

Back 49

losing

Front 50

causes of ground water contamination

Back 50

-sources of pollution
-plumes
-aggravation by pumping wells

Front 51

effect of ground water action; caves, speleothems (stalactites and stalagmites), sinkholes, spring

Back 51

Karst features

Front 52

continental scale glaciation at high latitudes (polar regions)

Back 52

continental glaciation

Front 53

glaciation in mountainous regions-- high elevations

Back 53

alpine glaciation

Front 54

theory of glacial ages; cyclic climatic changes related to orbital forcing

Back 54

global changes in climate

Front 55

theory of glacial ages; as water is tied up in glacial ice sea level drops, as glaciers melt sea level rises

Back 55

global changes in sea level

Front 56

maximum extent of glaciers at approx. 18,000 years ago, entered interglacial at approx. 10,000 years ago (beginning of Holocene)

Back 56

Pleistocene Glacial Maximum

Front 57

global distribution; ___% of glacial ice in Antartica

Back 57

85

Front 58

___% of glacial ice in Greenland

Back 58

10

Front 59

___% of glacial ice in Alpine glaciers

Back 59

5

Front 60

___% of world's fresh water tied up in glaciers

Back 60

volume of water

Front 61

type of glacier and characteristics; occupy valleys in mountainous regions

Back 61

valley (alpine) glaciers

Front 62

type of glacier and characteristics; continental size, can be kilometers thick

Back 62

ice sheets

Front 63

snow becomes compacted into firn then eventually recrystallizes into glacial ice

Back 63

glacier ice formation

Front 64

glacial ice budget; region in upper part of glacier where more snow accumulates than melts resulting in ice being added to the glacier

Back 64

zone of accumulation

Front 65

glacial ice budget; region in lower part of glacier where more snow/ice melts than accumulates resulting in loss of glacial ice

Back 65

zone of ablation

Front 66

glacial ice budget; line between the zone of accumulation and zone of ablation at the end of the warm season-- can usually be seen as the line separating white snow on the surface of the upper part of the glacier from darker snow/free ice in the lower part of the glacier

Back 66

equilibrium line

Front 67

glacial ice budget; if the equilibrium line advances down the valley it indicates a net gain in glacial ice and the glacier is advancing; if the equilibrium line moves up the valley, it indicates a net loss in glacial ice and the glacier is said to be retreating

Back 67

advancing vs. retreating systems

Front 68

meltwater often forms near the base of glaciers and can act as a lubricant to faciltate basal sliding

Back 68

basal sliding

Front 69

the top part of glaciers (to a depth of approx. 40m) deforms in a brittle fashion and is called the ____
- this part of the glacier mostly just goes along for the ride on top of the lower part of the glacier which due to the pressure of the overlying ice deforms in a plastic fashion

Back 69

rigid zone vs. zone of plastic flow

Front 70

the edges and base of the glacier move more slowly due to frictional drag on the bedrock

Back 70

velocity profile with depth

Front 71

form in the rigid zone, where the ice is under tension such as on the outside of curves in the valley or where the glacier goes over convex topography

Back 71

crevasses

Front 72

movement of ice sheets; glacial ice continental ice sheets tend to be very thick, so ___ flow in the lower part of the ice sheet dominates

Back 72

plastic flow

Front 73

formation of rock flour-- rock fragments trapped in ice at the base of the glacier grind away at the bedrock beneath

Back 73

bedrock grinding (abrasion)

Front 74

direction of flow indicators-- striations in bedrock can indicate the direction of previous glacial flow

Back 74

polished and striated surfaces

Front 75

streams tend to cut ___ shaped valleys

Back 75

V

Front 76

glaciers tend to cut ___ shaped valleys, with very steep walls and flat valley floors

Back 76

U

Front 77

alpine feature; steep ridges separtating valleys

Back 77

aretes

Front 78

alpine feature; steep peaks carved out by headward erosion of cirques on three or more sides

Back 78

horns

Front 79

alpine feature; half-bowl shaped forms eroded out by the upper parts of glaciers and through mass wasting

Back 79

cirques

Front 80

alpine feature; form where larger glacial valleys erode away the ends of aretes

Back 80

spurs

Front 81

alpine feature; form where smaller glacial tributary valleys are not eroded to the same extent as the major glacial valleys, often production spectacular waterfalls

Back 81

hanging valleys

Front 82

glacially deposited sediments that tend to be angular and very poorly sorted (glacial ice can carry everything from fine dust to house-sized boulders)

Back 82

till

Front 83

type of moraine; form in the center of large glaciers where lateral moraines form the edges of tributary glaciers come together

Back 83

medial

Front 84

type of moraine; deposits of till at the terminus of the glacier-- sub types are terminal moraines that form at the end of the farthest extent of the glacier, and recessional moraines that form as the glacier recedes

Back 84

end

Front 85

type of moraine; till deposited on the valley floor beneath the glacier

Back 85

ground

Front 86

type of moraine; mound-shaped deposits of till

Back 86

drumlins

Front 87

glacial outwash; deposits of reworked till that form in tunnels carved under glaciers by meltwater

Back 87

eskers

Front 88

glacial outwash; lakes that form as large blocks of ice melt in till deposits in outwash plains

Back 88

kettles

Front 89

glacial outwash; streams that form from meltwater at the snouts of glaciers tend to have heavy sediment loads and thus produce large numbers of gravel bars and large numbers of channels

Back 89

braided streams

Front 90

direct effect of past glaciation; fine grained wind blown deposits

Back 90

rock flour (loess)

Front 91

direct effect of past glaciation; mark the extent of past glaciation

Back 91

terminal moraines

Front 92

direct effect of past glaciation; ice sheets contributed to creation of the great lakes by widening existing stream valleys; finger lakes of new york formed through glacial till deposits damming up glacial valleys

Back 92

great and finger lakes

Front 93

indirect effects of past glaciation; formed from wetter conditions in glacial ages

Back 93

pluvial lakes

Front 94

indirect effects of past glaciation; water locked up in ice

Back 94

lowering of sea level

Front 95

indirect effects of past glaciation; drowned glacial valleys that formed as glaciers retreated and sea level rose

Back 95

fjords (fiords)

Front 96

evidence of older glaciation; evidence of temperature and greenhouse gases fluctuations preserved in ice cores from Antarctica and Greenland

Back 96

climate fluctuations

Front 97

evidence of older glaciation; lithified till deposits provide evidence of very old periods of glaciation

Back 97

ancient tillites

Front 98

dry areas, defined by annual rainfall <25 cm or aridity index of 4 or greater

Back 98

desert

Front 99

earth's wind system; related to thermal forcing at the equator-- warm moist air rises at the equator and cools-- dry air descends at 30 degree N and 30 degrees S latitudes, where most deserts are found

Back 99

Hadley Cells

Front 100

air loses moisture as it rises over mountains producing rain shadows on the downwind side

Back 100

rainshadows

Front 101

common desert feature; many desert regions have ___ ___ into low lying basins, forming shallow playa lakes

Back 101

internal drainage

Front 102

common desert feature; rare rain events can produce local intense floods

Back 102

flash floods

Front 103

common desert feature; dry stream beds through most of the year can become full rapidly during flash flooding events

Back 103

arroyos or dry washes

Front 104

tectonic province; produces strong rain shadow effects

Back 104

Sierra Nevada

Front 105

tectonic province; fault-block bounded mountain ranges with valleys in between

Back 105

basin and range

Front 106

tectonic province; region of flat lying sedimentary rocks at high elevation

Back 106

Colorado Plateau

Front 107

erosional features in order of decreasing size that form in flat-lying sediments due to differential weathering

Back 107

plateaus, mesas, buttes

Front 108

uplifted fault blocks that form mountain ranges

Back 108

horsts

Front 109

downdropped fault blocks forming valleys in between

Back 109

grabens

Front 110

common landform; cone shaped deposits of sediments at the mouths of mountain canyons

Back 110

alluvial fans

Front 111

common landform; shallow evaporate lakes that form in flat "playas" on the valley floors

Back 111

playa lakes

Front 112

common landform; form where alluvial fans coalesce

Back 112

bajadas

Front 113

wind picks up loose fine-grained material and moves sand via saltation (bouncing or skipping along the surface)

Back 113

erosion and transportation

Front 114

wind action; strong winds that pick up large quantities of dust

Back 114

dust storms

Front 115

wind action; features and mechanism of formation-- rocks abraded by wind blown sand

Back 115

ventifacts

Front 116

wind action; removal of fine-grained material by the wind-- may contribute to development of desert pavement

Back 116

deflation and blowouts

Front 117

loose fine-grained material from desert regions and/or glacial deposits of rock flour is picked up by the wind and deposited

Back 117

distribution of loess

Front 118

form from accumulation of sand transported by the wind through saltation and deposition on the slipface (the steep downwind side of the dune)-- can be preserved in the rock record as cross-bedded sandstones

Back 118

sand dunes

Front 119

wave characteristic; vertical distance from trough (low part) to crest (high part)

Back 119

wave height

Front 120

wave characteristic; horizontal distance from crest to crest or trough to trough

Back 120

wavelength

Front 121

wave characteristics; time for one wavelength to pass by a given point

Back 121

wave period

Front 122

wave characteristics; individual water particles move in near circular orbits as a wave passes by

Back 122

orbital particle motion

Front 123

wave characteristic; relationship to wavelength--particle motion diminishes with depth until it is gone at a depth of about 1/2 the wavelength

Back 123

wave base

Front 124

surf zone; as waves approach shore, they slow down, wavelength decreases and wave height is increased

Back 124

changes in wave characteristics

Front 125

surf zone; once the water depth is less than the wave base, the wave starts to "feel" the sea floor; the interaction of the sea floor and the wave results in drag on the orbiting water particles and slows the bottom of the wave

Back 125

relationship to wave base

Front 126

surf zone; the top of the wave continues to move more rapidly than the lower part and results in the wave toppling over or "breaking"

Back 126

formation of breakers

Front 127

near shore circulation; waves coming in at an angle to the shoreline feel the drag effects of the sea floor at one "end" of the wave first causing part of the wave to slow down, while the part of the wave that is still in deeper water continues to move more rapidly-- this causes the wave to bend until it becomes closer to parallel to the shoreline

Back 127

wave refraction

Front 128

near shore circulation; waves still coming in a small angle to the shore result in development of a current parallel to the shoreline known as a _______ ______

Back 128

longshore current

Front 129

result from water piling up along shore due to longshore currents; move seaward as narrow near surface currents in places of lower wave heights for incoming waves

Back 129

rip current

Front 130

beach structure; gently sloping landward part of beach

Back 130

berm

Front 131

beach structure; steeply sloping part of beach in swash zone)

Back 131

beachface

Front 132

drift features; form as spits extend all the way across the mouths of bays

Back 132

baymouth bars

Front 133

drift feature; sand deposits that form when longshore currents that move sand along the shoreline encounter deeper water in a bay and drop their sediment loads

Back 133

spits

Front 134

drift features; sand deposits that build up behind sea stacks (isolated islands near the coast)

Back 134

tombolos

Front 135

man-made structures designed to keep channels open, interrupt longshore currents and stabilize beach sediments, and maintain quiet waters

Back 135

jetties, groins, and breakwaters

Front 136

relative abundance

Back 136

sand sources

Front 137

erosional coasts; most wave energy absorbed by headlands

Back 137

wave focusing

Front 138

erosional coasts; erosion of headlands and deposition in bays results in _____ _____

Back 138

coastal straightening

Front 139

landforms; flat platforms cut by wave activity

Back 139

wave cut platforms

Front 140

landforms; erosional remnants of headlands

Back 140

sea stacks

Front 141

landforms; sea caves through eroded headlands that form ____

Back 141

arches

Front 142

islands that parallel coastlines with lagoons behind them

Back 142

barrier islands

Front 143

drowned coasts; flooded river valleys that formed as sea level rose

Back 143

estuaries

Front 144

drowned coasts; flooded glacial valleys that formed as sea level rose

Back 144

fiords

Front 145

drowned coasts; melting of glaciers led to rise in sea level

Back 145

relationship to glaciation

Front 146

old flat terraces that were below sea level that are exposed due to uplift

Back 146

marine terraces

Front 147

mangrove swamps and reef systems

Back 147

coasts shaped by organisms

Front 148

plate tectonic motions result in large horizontal forces

Back 148

tectonic forces

Front 149

tectonic force; for per unit area

Back 149

stress

Front 150

type of stress; squeezing together

Back 150

compressional

Front 151

type of stress; pulling apart

Back 151

tensional

Front 152

type of stress; shearing (sliding past)

Back 152

shear

Front 153

tectonic force; deformation that results from stress

Back 153

strain

Front 154

stress/strain relation in rocks; deformation involving breaking of the rock

Back 154

brittle deformation

Front 155

stress/strain relations in rocks; deformation in which the rock deforms plastically

Back 155

ductile deformation

Front 156

stress/strain relations in rocks; rapid strain rate tends to result in brittle deformation, slower strain rates can result in ductile deformation

Back 156

strain rate

Front 157

geological field method; the azimuth of a horizontal line in a plane

Back 157

strike

Front 158

geological field methods; the inclination of the plane; measured at 90 degree to strike

Back 158

dip

Front 159

maps showing geological formations and structural elements with strike and dip symbols to indicate the orientation of layers, faults, and folds

Back 159

geological maps

Front 160

representations of vertical slices through the earth

Back 160

cross-sections

Front 161

fold element; theoretical line that if moved parallel to itself will form the shape of the fold

Back 161

axis

Front 162

fold element; a planar surface containing the fold axis or hinge lines for each layer of the fold

Back 162

axial plane

Front 163

fold element; point of maximum curvature of the fold

Back 163

hinge

Front 164

fold element; sides of the fold

Back 164

limbs

Front 165

fold type; a fold with horizontal fold axis and a vertical axial plane

Back 165

upright

Front 166

fold type; a fold with a plunging (non-horizontal) fold axis

Back 166

plunging

Front 167

fold type; a fold with broad, open limbs

Back 167

open

Front 168

fold type; a fold with parallel limbs

Back 168

isoclinal

Front 169

fold type; a fold with an overturned (upside down) limb

Back 169

overturned

Front 170

fold type; a fold "lying on its side"

Back 170

recumbant

Front 171

upward arching folds with older rocks near the core of the fold

Back 171

anticlines

Front 172

downward arching folds with younger rocks near the core of the fold

Back 172

synclines

Front 173

circular upwarped

Back 173

domes

Front 174

downwarped structure

Back 174

basin

Front 175

fractures across which there has been little displacement; form perpendicular to tensional stress directions

Back 175

joints

Front 176

fractures across which there has been displacement

Back 176

faults

Front 177

slip in the direction of dip

Back 177

dip-slip

Front 178

refers to the block above the fault

Back 178

hanging wall

Front 179

refers to the block below the fault plane

Back 179

footwall

Front 180

faults where the hanging wall moves down relative to the footwall

Back 180

normal faults

Front 181

faults where the hanging wall moves up relative to the footwall

Back 181

reverse faults

Front 182

low angle (shallow dipping) reverse faults

Back 182

thrust faults

Front 183

slip is in the direction of strike; slip is mostly horizontal

Back 183

strike-slip

Front 184

relative motion between blocks moves fault block on the opposite side of the fault either to the right or left

Back 184

right-lateral vs. left-lateral

Front 185

components of both dip-slip and strike-slip motion

Back 185

oblique-slip