earth science quiz 8 prep

What is the difference between an ice sheet, sea ice, and an ice shelf?

An ice sheet exists entirely on land, an ice shelf floats in the sea but are still attached to land, and sea ice floats in the sea unattached to land.

Where is the world's largest ice sheet located today?

Antartica

What is cross bedding?

Layers deposited on a dune slip face that are inclined in the direction of wind transport.

Why does the crust uplift slightly on either side of a growing glacier?

Mantle under the glacier is pushed aside by sinking crust. This mantle pushes up the crust on either side of the glacier.

Why does glacial subsidence NOT occur at the exact moment that a glacier forms?

The rate of subsidence is controlled by the rate at which mantle can flow.

If accumulation exceeds ablation in a glacial budget, which of the following will happen?

The terminus will move downhill ("advance").

What formed this valley's distinctive "U" shape?

glacial erosion

A landscape dominated by U-shaped valleys and pyramid-shaped mountains is most likely formed due to ________.

glaciation

Which one of the following is an evaporite mineral? -clay -gypsum -calcium -quartz

gypsum

What glacial feature is circled in Figure 2?

horn

How do glaciers move?

ice mass sliding along the ground plastic flow of ice

What is the largest type of glacier?

ice sheet

When desert pavement is produced in a desert, why do the larger particles accumulate on the surface?

The wind can move particles of only a very specific size and it takes away these small particles, concentrating the larger ones.

In the desert environment, how are ventifacts created?

Ventifacts are produced on the surface of a rock by the continued impact of very small particles carried by the wind.

Which of the following statements about deserts is true? Deserts are always hot. Deserts are lifeless. Water is the most significant agent of erosion in deserts. Wind is the most significant agent of erosion in desert regions. Deserts are dominated by sand dunes.

Water is the most significant agent of erosion in deserts

When alluvial fans enlarge and coalesce in the Basin and Range mountain desert environment, what feature do they form?

a bajada

When alluvial fans enlarge and coalesce in the desert environment in the Basin and Range region, what feature do they form?

a bajada

How does a medial moraine form?

a medial moraine is the result from the merging of two glaciers, causing their lateral moraines combining to form a medial moraine.

When a valley glacier leaves the mountains and enters the relative flat lands below, it may spread out to form ________.

a piedmont glacier

Which of the below are depositional features created by glaciers? PLEASE SELECT ALL THAT APPLY. drumlins kames cirques eskers outwash plains

all but cirques

Deflation may lead to ________.

all of the above

A(n) ________ is a cone of debris that forms where an ephemeral stream emerges from the confines of the canyon. Its runoff spreads over the gentler slopes at the base of the mountains and quickly loses velocity, dumping most of its sediment load within a short distance.

alluvial fan

Check the box for and double-click the Zagros Mountains, Iran placemark. What type of feature is the placemark on?

alluvial fan

Check the boxes for the Telescope Peak, CA and One placemarks and then double-click the Telescope Peak, CA placemark. This placemark takes you to Dante's View in Death Valley, CA. You are overlooking Badwater, the lowest location in North America, at 82 m below sea level. What type of feature is under the One placemark?

alluvial fan

What is a playa commonly occupied by?

an ephemeral lake

Which of the following is a feature of a desert environment? -a meandering stream system -an extensive tributary system -an ephemeral stream -a forest -a crevasse

an ephemeral stream

What is the largest type of glacier?

an ice sheet

Ephemeral streams ________.

are a major agent of erosion in desert regions

What glacial feature is circled in Figure 1?

arête

In an area of alpine glaciation, sinuous, sharp-edged ridges called ________ and sharp, pyramid-like peaks called ________ are common features.

arêtes; horns

Check the box for and double-click the MANY folder. Each of the placemarks in the image identifies another example of the same feature indicated by the One placemark. What is the term for the landform created when several such features have coalesced into a continuous surface?

bajada

If ice accumulation equals the amount of ice lost, the glacier will ________.

become stationary

At what latitudes do the large-scale, convection cells bring dry air downward toward the Earth's surface?

between 20-30° north and south

Deselect the One and Many placemarks and check the Death Valley, CA and Dante's View placemarks. Double-click the Death Valley, CA placemark. What is the term for the landscape feature from Telescope Peak to the west to Dante's View to the east?

bolson

If you were on a geology field trip in an area of glacial deposition, how would you distinguish between samples of till and stratified drift?

by comparing their grain size and sorting

Deflation leads to the formation of desert pavement by __________.

carrying fine sediments away and leaving a layer of larger particles at the surface

________ are erosional features produced by valley (alpine) glaciers.

cirques

A hazard people face when crossing a glacier is falling into a ________, a large crack that extends through the zone of fracture.

crevasse

Wind erosion can cause __________, which can create shallow depressions called __________.

deflation; blowouts

In the second model, wind energy diminishes between large grains of the surficial layer, leading to what?

deposition of fine-grained sediments between large grains

Course-grained sediments such as pebbles and cobbles often comprise the ________ in desert environments.

desert pavement

Which of the following is a feature of a desert environment?.

ephiermal stream

A sinuous ridge composed of sand and gravel is a(n) ________; it is a deposit made by streams flowing in tunnels within or beneath glacial ice.

esker

Arêtes, horns, and U-shaped valleys are depositional features made of till. (T/F)

false

Melting and calving are two forms of accumulation. (T/F)

false

Steppes are the driest of the true desert lands. T/F

false

Desert regions occur __________, and always have a(n) __________ climate zone adjacent to them.

on every continent; steppe

Match the landscape feature with the material from which it is formed.esker

outwash

Check and double-click the Badwater placemark. What is the term for the central salt pan in the valley?

playa

How do pieces of rock move under the influence of wind?

rolling, sliding, bouncing, suspension

What is the term for the rolling and bouncing of sand grains during transport?

saltation

________ is the process of sand grains bouncing or rolling along the surface.

saltation

When air __________, it is compressed and warmed.

sinks

What property of a piece of material will most directly determine how it is carried by wind?

size

Cross-bedded sandstone shows inclined beds in a downward direction. What part of the ancient dune do these features represent?

slip face

Match the landscape feature with the material from which it is formed.cirque

solid rock

A(n) ________ is defined as a semiarid climate.

steppe

Which glacial feature indicates the maximum extent of a glacier?

terminal end moraine

What is the snow line?

the elevation above which snow persists throughout the year

How do loess deposits differ from sand deposits? PLEASE SELECT ALL THAT APPLY.

the grains that make up loess deposits have generally traveled a farther distance before deposition than a sand deposit. Some of the loess in loess deposits has come from glacial outwash deposits, whereas sand in sand deposits does not come from glacial outwash deposits. Sand deposits are made of larger grains than loess deposits, which are made of silt-sized grains.

What is the zone of wastage?

the part of a glacier where snow melting exceeds snow accumulation

What is dust?

the particles carried in suspension by wind

Deserts that lie outside of the subtropics and mid-latitude belts are most likely the result of __________.

the presence of a rainshadow

What is isostasy?

the rising and sinking of Earth's crust relative to the mantle in response to the redistribution of mass on the surface

Which one of the following is NOT true of glaciers?

they exist only in the Northern Hemisphere

For how long will land rebound after a glacier melts?

thousands of years

Although infrequent, running water is responsible for most of the erosional work in deserts. (t/f)

true

Bajadas develop when multiple alluvial fans grow and merge along the fronts of mountain ranges in arid lands. (T/F)

true

Examine the photo. Is it true or false to say, "the dunes that deposited these cross beds were moving from the left to the right"?

true

Glaciers are part of the hydrologic cycle. T/F

true

Till is unsorted sediment deposited directly from the melting glacial ice; stream action is not involved. T/F

true

What is the best way to describe the shape of a glacial valley?

u-shaped

Most of the erosion that took place during the "Dust Bowl" years of the 1930s in the Great Plains of North America was the result of which of the following processes?

wind

Which of the following is the least effective agent of erosion?

wind

Precipitation occurs on the __________ of the mountain range, while the __________ is dry.

windward side; leeward side

Where do crevasses form?

zone of fracture

Which of the below are features created by glacial erosion that you might see in an area where valley glaciers recently existed? PLEASE SELECT ALL THAT APPLY. -polished rock on the surface of the bedrock -grooves parallel to the direction of the glacier's movement on the surface of the bedrock -grooves perpendicular to the direction of the glacier's movement -moraines perpendicular to the glacier's direction of movement -moraines parallel to the glacier's direction of movement

-polished rock on the surface of the bedrock -grooves parallel to the direction of the glacier's movement on the surface of the bedrock

About what percentage of Earth's land surface is covered by deserts?

30%

What is the natural angle of repose for sand?

34 degrees

Greenland's ice sheet covers about ________ of the island.

80%

Why does the crust subside slightly on either side of a melting glacier?

Crust under the glacier rises as the ice melts. This allows mantle on either side of the glacier to move to areas under the glacier.

Which of the four lettered positions on this map-view sketch shows the location of the terminal end moraine?

D

Which of the following is true about sand dunes?

Dunes move over time.

Which of the following statements characterizes ephemeral streams?

Ephemeral streams flow only at certain times of the year.

Loess consists mainly of sand-sized particles. (T/F)

False

In the first model, what happens as the layer of coarse material develops at the surface?

It blocks the fine-grained sediment below from the wind, which prevents the possibility of further deflation.

What is the primary difference between the two desert pavement hypotheses?

Model 1 is based on a sediment volume decrease through time (erosion), while Model 2 is based on an increase in sediment volume through time (deposition).

__________ are defined as a chain of glacial lakes where each lake flows into the next.

Pater noster lakes

What does saltating mean?

Sand grains are lifted by the wind, leap a short distance, and then fall back to the ground.

How is desert different from steppe?

Steppe is more humid than desert.

What will happen to the crust as a glacier grows?

The crust under the glacier will sink into the mantle.

Please describe the features and characteristics associated with each stage in the evolution of a mountainous desert.

The early stage includes playa lakes from intermittent rainfalls and alluvial fans at the mouths of canyons; the middle stage includes bajadas that have formed when alluvial fans coalesced together and playas that resulted from the evaporation of water from playa lakes; the late stage includes inselbergs, which are towers of bedrock that are the eroded remainders of the mountains that once existed.

How rapidly does glacial ice move?

The movement of glacial ice varies between glaciers, but is generally very slow.

Where are drumlins formed?

in areas of ground moraine

Where do glaciers form?

in places where more snow falls in the winter than melts away in the summer

A rainshadow desert forms ________.

in places where mountain ranges act as barriers to the movement of water vapor

A glacier's downstream end ________.

is in the zone of wastage

This cobble shows prominent scratches because ________.

it was scraped against other rocks in a glacier

The __________ of a dune is characterized by a decrease in energy and sand avalanches, which occur due to oversteepening.

leeward slide

Dust storms are most likely to deposit windblown silt, commonly called ________.

loess