Geology Exam 4

Since many desert regions have internal drainage, runoff collects on the valley floors as bajadas.

False

The amount of fresh water stored in oceans is many times greater than the amount of ground water.

False

The saturated zone overlies the water table.

False

The site selected for the disposal of high level radioactive waste is the ocean.

False

The thicker part of a glacier will flow slower than where it is thinner.

False

The two types of glaciated terrain on the Earth's surface are alpine and valley.

False

Ventrifacts are rocks with rounded water-abraded surfaces.

False

Wave orbits decrease in size until motion is gone at a depth equal to twice wavelength.

False

When water is pumped from a well the water table is typically drawn down into a zone of depression.

False

... has extensive loess deposits up to 100 meters thick.

China

This area of the desert southwest is characterized by mostly flat-lying beds of sedimentary rock over 1,500 meters above sea level.

Colorado Plateau

... states that the velocity of ground water equals permeability multiplied by hydraulic gradient.

Darcy's law

In parts of Texas and New Mexico the pumping of ground water has caused the water table of the Ogallala Reservoir to drop ...

30 meters

A deposit of loose sand may have a porosity of ... percent.

30-50

The angle of repose of sand-sized particles falling from the air is ... degrees.

34

For the past 3000 years sea level has been rising at a rate of ...

4 cm per century

A worldwide decrease of at least ... degrees C in temperature would bring about a new glacial age.

5

The down-valley part of a glacier is the ..., where melting, evaporation, and calving take place.

zone of ablation

Most dunes move only ... per year.

10 to 15 meters

A butte is a narrow valley with a narrow bottom and flat sides.

False

A mesa is capped by sedimentary rocks while a butte is capped by a lava flow.

False

A playa lake is a deep long-lasting desert lake.

False

A transverse dune is a relatively straight, elongated dune oriented parallel to wind direction.

False

An end moraine marks the final edge of a receding glacier just before the glacier melts away entirely.

False

An esker is a long sinuous ridge of ice.

False

An irregular coast with bays separated by headlands can be straightened by plate tectonic forces.

False

Barrier islands are associated with an erosional coastline.

False

Dune sand throughout the world is composed of the stable mineral quartz.

False

Estuaries, such as Chesapeake Bay, are drowned glacial-cut valleys.

False

Glaciers in temperate climates may have crevasses that extend to their base.

False

Glaciers in temperate climates tend to move slower than those in colder regions.

False

Gravel beaches are found on coasts with low wave energy.

False

In passing over a dune, wind scours sand from the downwind or slip face.

False

More sand is moved along the beach face than in the surf zone.

False

Waves usually come straight into shore.

False

Some ... beaches are made up of sand-sized particles of basalt.

Hawaiian

A U-shaped valley (in cross section) is characteristic of glacial erosion.

True

Thin rocky soil and slow rates of creep make desert topography steep and angular.

True

Shale is a common ... because it retards the flow of ground water.

aquitard

... streams receive water from the saturated zone.

gaining or effluent

Given all other conditions are the same, ground water flows faster if ...

it is flowing in response to a greater hydraulic gradient

Wave orbits decrease in size with depth, and motion is essentially gone at a depth of ...

one half wavelength

The sediment deposited by debris-laden melt water is called ...

outwash

A ... dune is deeply convex and its horns point upwind.

parabolic

You can get out of a rip current easily by swimming ... to the beach instead of struggling against the current.

parallel

Above the rigid zone, glacial ice movement is due to ...

passive riding of the ice on the glacier

Most ... and ... are both porous and permeable.

sandstone; conglomerate

... are icicle-like pendants of calcite hanging from cave ceilings.

stalactites

The unsaturated zone is ...

the zone above the water table

In unconfined aquifers water in shallow wells ...

will rise to the level of the water table

This agent of erosion and deposition is most effective on fine sediment that is dry.

wind

Groins are short walls built parallel to shore to keep sand from moving.

False

Jetties and groins work because they enhance the flow of sand along a beach.

False

Petrified wood develops when buried wood is saturated or replaced with calcite.

False

Sandstones and gravels make the only aquifers; no other rocks are useful.

False

Seawalls are constructed perpendicular to the shore to prevent wave erosion.

False

... first suggested that glacial/interglacial episodes are related to variation in solar radiation cycles.

M. Milankovitch

A baymouth bar is a ridge of sediment that cuts a bay off from the open ocean.

True

A desert is any region which has a dry or arid climate with a low rainfall of less than 25 cm per year.

True

A fiord is a glacially-cut valley flooded by rising sea level.

True

A large trunk glacier erodes downward more rapidly and carves a deeper valley than do smaller tributary glaciers.

True

A particle of water in a wave moves in a circular orbit as the wave passes; the particle returns to its original position after the wave has passed.

True

A pediment is an erosional surface underlain by solid rock, while a bajada is depositional and is underlain by sediment.

True

A tombolo is a bar of sediment connecting a former island to the mainland.

True

An unconfined aquifer is recharged rapidly, whereas a confined aquifer recharges slowly.

True

Artesian wells are associated with confined aquifers.

True

Because sand-sized grains are heavier than silt or clay-sized grains, sand moves close to the ground in a series of short hops called saltation.

True

Bodies of till shaped into streamlined hills are called drumlins.

True

Compared to the flow of water in streams, most ground water moves relatively slowly.

True

Deposits of calcite built up in caves by dripping water are called dripstone or speleothems.

True

Dune types are influenced by wind velocity.

True

During the most recent ice age, sea level was at least 100 meters lower than at present.

True

Gasoline leaked from gas station storage tanks is less dense than water and can rise to the top of the water in an aquifer.

True

Glaciers are part of the hydrosphere.

True

Glaciers with a positive budget are advancing glaciers.

True

Gravel beaches have a steeper face slope than sand beaches.

True

Gravel has both high porosity and excellent permeability.

True

Groundwater is a major economic resource.

True

How fast groundwater flows depends, in part, on the permeability of the sediment through which it passes.

True

In confined aquifers the water is under pressure and rises to a level above the top of the aquifer.

True

Loess is a deposit of wind-blown silt primarily composed of unweathered angular grains of quartz and feldspar.

True

Longshore currents transport most of the beach sand parallel to the shoreline.

True

Most sand dunes are asymmetric in cross section with a gentle slope facing the wind and a steeper slope on the downwind side.

True

Rapid down cutting of desert stream channels produces narrow canyons with vertical walls and flat gravel-strewn floors.

True

Some of the world's deserts are the result of the rain shadow effect of mountain ranges.

True

Springs may form where a perched water table intersects the surface.

True

Stacks are erosional remnants of headlands left behind as the coast retreats.

True

Striations and grooves in bedrock indicate that direction of ice movement.

True

Support is growing for the idea that a late Precambrian ice sheet was so extensive that the surface of the world ocean was frozen.

True

The Basin and Range province is characterized by rugged mountain ranges bounded by faults.

True

The addition of new water to the saturated zone is called recharge.

True

The capillary fringe is thicker in fine-grained sediments and thinner in coarse-grained sediments.

True

The compacted mass of granular snow, transitional between snow and ice, is called firn.

True

The highest wind wave ever measured was 34 meters high.

True

The primary control of glacial-interglacial episodes seems to be variation in the Earth's orbit and inclination to the sun.

True

The rate of ground water flow tends to decrease with depth because sedimentary rock pores tend to be closed by increasing amounts of cement and the weight of the overlying rock.

True

The world's best-known deserts lie in a belt 10-15 degrees centered at latitude of 30 degree (North and South).

True

Tillite is lithified till.

True

Two layers of sediment representing one year of deposition in a lake are called a varve.

True

Unsorted and unlayered rock debris carried or deposited by glaciers is called till.

True

Water in the upper part of the saturated zone tends to move downward following the slope of the water table.

True

Wavelength is the horizontal distance between two wave crests or two troughs.

True

Where glaciers exist they are far more effective agents of erosion, transportation, and deposition than running water.

True

Where sand supply is limited a barchan dune generally develops.

True

Winter beaches build up underwater sandbars that serve as a storage facility for next summer's sand supply.

True

A(n) ... -shaped valley (in cross section) is characteristic of glacial erosion.

U

The longest ice core drilled was obtained at ..., Antarctica, in the 1990s.

Vostok

A large trunk glacier carves a deeper valley than smaller tributaries. After the glacier disappears the tributary valley remains as ... high above the main valley.

a hanging valley

Under the influence of gravity a glacier moves down valley and eventually ...

ablates

Rock debris picked up in flash floods is deposited at the base of mountains in ...

an alluvial fan

A(n) ... is a body of saturated rock or sediment through which water can move easily.

aquifer

Which of the following would not be a control on desert development?

areas beneath rising air masses

Sharp ridges called ... separate adjacent glacially carved valleys.

aretes

Desert stream channels called ... are characterized by narrow canyons with vertical walls and flat, gravel-strewn floors.

arroyos

In a(n) ... aquifer water rises above the top of the aquifer when a drill penetrates it.

artesian

A(n) ... is a broad gently sloping surface formed by the coalescing of alluvial fans.

bajada

The "horns" in a ... dune point in a downwind direction.

barchan

Where sand supply is limited a ... dune usually forms.

barchan

The steepest part of a beach is the ...

beach face

Dunes are not just desert features, they are commonly found near ...

beaches

Most caves are probably formed by ground water circulating ... the water table.

below

The upper part of a beach landward of the high tide line is the ...

berm

A ... is a depression on the land surface caused by wind erosion which may have a pillar left at the center.

blowout

A ... is a structure built to absorb the force of large, offshore breaking waves and provide quiet water near shore.

breakwater

A ... is a narrow hill of resistant rock with a flat top and very steep sides found in some deserts.

butte

... form when slightly acidic ground water dissolves limestone along joints and bedding planes.

caves

What caused the glacial ages?

changes in circulation of sea water, changes in the atmosphere, changes in the positions of the continents, and the cause is unknown at this time.

A(n) ... is a steep-sided half-bowl shaped recess carved at the head of a mountain glacial valley.

cirque

... are landscape features that indicate a mountainous area has been glaciated.

cirques, horns, and aretes

A ... encompasses all land near the sea, including the beach and a strip of land inland from it.

coast

How do deserts form in coastal tropical regions?

cold ocean currents

When water is pumped out of an unconfined aquifer through a well, a ... often develops in the water table.

cone of depression

A(n) ... aquifer is completely filled with water under pressure and is separated from the surface by an aquitard.

confined

Open fissures called ... develop in the brittle surface ice of glaciers.

crevasses

Once a glacier is gone the land begins to uplift slowly to its pre-glacial height, a process called ...

crustal rebound

... gives us more evidence of the beginning and ending times of glacial episodes than the direct study of glacial deposits.

deep ocean sediment

The removal of clay, silt, and sand particles from a land surface by wind is called ...

deflation

U.S. coasts with gently sloping plains, such as those along the Atlantic and Gulf of Mexico, are ...

depositional

Glaciers can be considered as ... of fresh water for future use.

deposits

... is a thin surface layer of closely packed pebbles found in deserts.

desert pavement

... is a hard shiny coating of dark iron and manganese oxides and clay minerals that form on rock surfaces in arid environments.

desert varnish

The expansion of deserts into once populated areas is known as ...

desertification

The height and length of a wave is a function of ...

distance over which the wind blows, wind duration, and wind strength

Local lowering of the water table, called ..., tends to change the direction of groundwater flow by changing the slope of the water table.

drawdown

Heavy use of ground water can cause a region's water table to ...

drop to deeper depths

Bodies of till shaped into streamlined hills are called ...

drumlins

The hydraulic head is defined as ...

elevation plus pore fluid pressure at a given moment

The boundary between the zone of accumulation and the zone of ablation is an irregular line called the ...

equilibrium line

A(n) is an ice-transported boulder that was not derived from the underlying bedrock.

erratic

A(n) ... is a long sinuous ridge of water-deposited cross-bedded and well-sorted sediment deposited by a stream that flowed within or under a glacier.

esker

The central portion of a valley glacier moves ... the sides.

faster than

A(n) ... is a coastal inlet that is formed by a drowned glacial carved valley.

fiord

Drowned coasts may be marked by ..., glacially cut valleys flooded by rising sea level.

fiords

The high runoff following sporadic desert downpours can create sudden local floods called ...

flash floods

Tidal deltas are usually associated with ...

gaps in barrier island systems

A ... is a type of hot spring that erupts hot water and steam.

geyser

The theory of ... states that at times in the past, colder climates prevailed during which much more of the land surface was glaciated than at present time.

glacial ages

Loess deposits in the U.S. Midwest are derived from ...

glacial outwash of the Pleistocene age

... are sometimes built perpendicular to shore in an attempt to protect beaches that are losing sand from longshore drift.

groins

As ice retreats by melting back, the rock debris carried by the glacier is deposited to form a relatively thin layer of till called a(n) ...

ground moraine

A wave begins to "feel the bottom" at a water depth equal to ...

half a wave length

... water is water that contains relatively large amounts of dissolved calcium and magnesium.

hard

Waves break because ...

height increases while length decreases

A(n) ... is the sharp peak that remains after cirques have cut back into a mountain on several sides.

horn

Ordinary ocean waves are created by the interaction of the ... and ....

hydrosphere, atmosphere

A(n) ... is a mass of ice that is not restricted to a valley but covers large areas of land.

ice sheet

If a moving glacier reaches a body of water ... float free.

icebergs

An ... rock is one that does not allow water to flow through it easily.

impermeable

Gasoline leaking from an underground storage tank will ...

infiltrate to the top of the water table, on which it will float

... are rock walls designed to protect the entrance of a harbor from sediment deposition and storm waves.

jetties

An are with many sinkholes and caves is said to have ... topography.

karst

When an ice block that was buried in sediment finally melts a depression called a ... forms.

kettle

... moraines are elongate low mounds of till that form along the sides of valley glaciers.

lateral

... dunes in the Sahara are as high as 200m and as long as 120km.

longitudinal

A large dune type is the ... (or seif) dune, which forms a ridge parallel to prevailing wind direction.

longitudinal

Waves arriving at an angle to the shore push water parallel to the shore in a ...

longshore current

Vast amounts of sand are moved by ...

longshore currents

... is the movement of sand parallel to the shore.

longshore drift

In very dry climates such as deserts, rivers tend to be ...

losing streams

The amount of ground water is ... that of all rivers and lakes combined.

many times

Where tributary glaciers come together the adjacent later moraines join to form a ... moraine.

medial

The sea level rise in the past 15,000 years is due to ...

melting glaciers

The Colorado Plateau is marked by peculiar, step-like bends in rock layers called ...

monoclines

A(n) ... is a gently sloping erosional surface, commonly covered with a veneer of gravel, cut into the solid rock of a mountain.

pediment

A(n) ... is a body of ground water separated from the main water table by a zone that is not saturated.

perched water table

... refers to the ability of a rock to transmit fluids.

permeability

Shales can have substantial porosity but have low ...

permeability

Groundwater is important in the preservation of ... which develops when porous buried wood is either filled in or replaced by inorganic silica in by ground water.

petrified wood

When the desert sun dries a lake, a very flat surface underlain by hard mud-cracked clay called a ... may form.

playa

Not all deserts are hot. Descending air near the North and South poles creates ... deserts.

polar

... is the percentage of a rock or sediment that consists of void space.

porosity

U.S. deserts in Nevada and northern Arizona are largely the result of the Sierra Nevada Mountains ...

rain shadow

If the terminus of a glacier remains stationary for a few years a distinct ... may form.

recessional moraine

... are narrow currents that flow straight out to sea in the surf zone.

rip currents

... carry fine-grained sediments out of the surf zone into deeper water.

rip currents

Sand moving over a dune surface by saltation typically forms ...

ripple marks

If all ice sheets were to melt, sea level would ...

rise by over 60 meters

The greater part of the sand from most beaches comes from ...

rivers

The grinding of rock against rock by a glacier produces a very fine sediment called ...

rock flour

The water table ... in humid regions.

roughly parallels the land surface

The net effect of wave ... is to move sand in a series of arcs along the beach face.

run up and return

... is the dominant agent of erosion in desert regions.

running water

... is becoming a serious problem as demand for drinking water increases in coastal cities.

salt-water intrusion into wells

Because sand grains are heavier than clay and silt particles, sand grains move close to the ground in a leaping pattern called ...

saltation

Heavily pumped wells near a coast can be contaminated by ...

saltwater intrusion

High-speed winds can cause ..., clouds of sand moving rapidly near the land surface.

sand storms

Wave erosion of headlands produces ..., steep slopes that retreat inland by mass wasting as wave erosion undercuts them.

sea cliffs

... are closed depressions found where land surfaces are underlain by limestone bedrock.

sinkholes

The steep downwind face of a sand dune is called the ...

slip face

A ... is a ridge of sediment that cuts a bay off from the ocean.

spit

Sediment may build up off a point of land to form a ...

spit

A ... is a place where water flows naturally from rocks onto the ground surface.

spring

... coasts are common because sea level has been rising for the past 15,000 years.

submergent

During what season can you find the best beaches?

summer

Waves breaking along the shore are known as ...

surf

A(n) ... is a lake occupying a bedrock depression excavated by a glacier.

tarn

The ... is the end of a glacier.

terminus

An area with desert conditions in the United States is ...

the Colorado Plateau

... are the product of past glaciations.

the Great Lakes

In the United States, large areas of ... are blanketed with a cover of loess.

the Midwest

Water in ... has lost its orbital motion and moves back and forth.

the surf zone

Deflation continues to deepen a blowout until is reaches ...

the water table

The energy that moves sand along a beach ultimately comes from ...

the wind

A glacier will flow faster where it is steeper and ...

thicker

Because of their low rainfall, intermittent stream flow, and dry stream beds, desert lack ...

through-flowing streams

A ... is a bar of sediment that connects a former island to the mainland.

tombolo

... is a deposit of calcite that forms around hot springs.

travertine

... are wave cut platforms formed by erosion of rock associated with cliff retreat.

uplifted marine terraces

The ... is the zone above the water table.

vadose zone

Two layers of sediment resulting from one year's deposition in a glacial lake are called ...

varves

Wind-blown sand may sculpt isolated pebbles, cobbles, or boulders into ...

ventifacts

The upper surface of the saturated zone is called the ...

water table

Coastal straightening occurs because of ...

wave erosion of headlands and deposition in bays

The diameter of the orbital path of a water particle near the surface is equal to ...

wave height

The vertical distance between the crest and the trough of a wave is called the ...

wave height

The horizontal distance between two wave crests is called the ...

wave length

The bending of waves as they enter shallow water is called ...

wave refraction

A ... is a deep, cylindrical hole that is dug or drilled into the ground to penetrate an aquifer within the saturated zone.

well

Sand grains found in dunes are commonly ...

well sorted and well rounded

The upper part of a glacier, the part with perennial snow and ice, is called the ...

zone of accumulation