Geology 4

________ are steep-sided hills composed mostly of stratified drift.

Kames

Identify the alpine glacial features indicated by the letter A in the below block diagram.

cirques

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

desert pavement

Which glacial feature indicates the maximum extent of a glacier?

terminal end moraine

Which glacier deposit are drumlins mainly composed of?

till

What is the most important erosional agent in deserts?

water

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

Antarctica

Define dry climate. How extensive are the desert and steppe regions of Earth?

Dry climate is a climate in which yearly precipitation is less than the potential loss of water by evaporation. Desert and steppe regions cover about 30 percent of Earth's land surface

Which of the following statements characterizes ephemeral streams?

Ephemeral streams flow only at certain times of the year.

The cross bedding in a preserved layer of sandstone dips (tilts downward) to the East. What can be inferred about the wind direction at the time of deposition?

From West to East

Which of the following responses best defines the movement of ice within a glacier?

Glacial movement is always in a downslope direction.

________ are long, linear scratch marks carved onto bedrock by glacial abrasion.

Glacial striations

How do glaciers fit into the hydrologic cycle, and what roles do they play in the rock cycle? PLEASE SELECT ALL THAT APPLY.

Glaciers fit into the hydrologic cycle when precipitation that falls at high elevations does not immediately make its way toward the sea. Instead, it may become part of a glacier. Ultimately, the glacial ice will melt into water, which will continue on its path to the sea. Glaciers play a role in the rock cycle by being dynamic erosional agents that accumulate, transport, and deposit sediment.

What are cross beds?

Inclined layers in sediment or sedimentary rocks that reveal the direction of wave or wind transport

large bedrock knobs projecting above a sediment-filled basin

Inselberg

This cobble shows prominent scratches because ________.

It was scraped against other rocks in a glacier.

Why is wind erosion relatively more effective in arid regions than in humid areas? PLEASE SELECT ALL THAT APPLY.

Moisture in humid areas binds particles together, which inhibits wind erosion. Vegetation in humid areas anchors down the soil, which inhibits wind erosion.

a dry, flat lake bed

Playa

center of basin where streams flow and briefly accumulate before evaporating or infiltrating bedrock

Playa lake

encrusted salt layer left behind once water evaporates

Salt flat

How is desert different from steppe?

Steppe is more humid than desert.

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

a piedmont glacier

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

What is the largest type of glacier?

an ice sheet

What is an ephemeral stream?

an intermittent stream that carries water only in response to specific episodes of rainfall

Identify the alpine glacial features indicated by the letter C in the above block diagram.

arête

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

arêtes; horns

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.

What is the difference between till and stratified drift?

Till is an unsorted type of glacial drift, whereas stratified drift is sediment that is sorted according to the size and weight of particles.

An apron of sediment along a mountain front created by the coalescence of alluvial fans.

bajada

What is the name used for cracks in the upper portion of a glacier?

crevasses

Examine the photograph above. What type of depositional feature is shown?

cross bedding

A rainshadow desert forms ________.

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

Which of the following is an example of a glacial deposit?

moraine

Cirques often contain small lakes called ________.

tarns

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

Where is the focal point of a glacier's growth?

in a cirque

a fan-shaped deposit formed when a stream's slope is abruptly reduced

Alluvial fan

What is the desert land form shown in Figure 1? (Expand the window if you can't see the whole picture.)

An aluvial fan

What do we call the isolated pinnacle of bedrock shown in Figure 5?

An inselberg

What do we call the gently sloping apron of sediment seen on the far side of the valley in Figure 3? It formed as alluvial fans merged.

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.

What do we call this flat area which is created when a desert lake dries out like the one in Figure 2?

A playa

What do we call a shallow, often temporary body of water in a desert basin like the one in Figure 4?

A playa lake

The terminus of a glacier will advance when which of the following conditions is met?

Accumulation of snow is greater than wastage

Cross beds are a preserved record of what?

The deposition of sand on the leeward side of a dune.

Relate the glacial budget to the two zones of a glacier

The glacial budget is the balance or lack of balance between the gain of snow in the zone of accumulation and the loss of ice in the zone of wastage.

Why is it difficult to reconstruct the glacial episodes of the Pleistocene Ice Age from the glacial record on land?

The glacial record on land is punctuated by many erosional gaps.

Working in a mountain valley that contains an alpine glacier, you discover a series of end moraines in the valley. As you move up toward the glacier, what conclusions can you expect to make about the moraines?

The moraines get younger as you get closer to the glacier.

During the Cold War, a B-52 bomber accidentally dropped an unarmed nuclear device on the Greenland Ice Sheet. Upon returning to the drop zone many years later, the device had gone missing. As a glaciologist on the project, where should you look for the missing device?

To find it you should go downslope from the drop zone, in the direction of ice flow.

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?

Water is the most significant agent of erosion in deserts.

Why do desert dunes migrate?

Wind erodes material on the windward side of the dune and deposits it on the leeward side of the dune.

What is the name used for random boulders left behind by a glacier?

erratics

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

When a glacial trough is "drowned" by the sea, the result is a(n) ________.

fiord

What is the name used for steep-sided inlets of the sea created when a glacial valley was flooded as sea level rose?

fjord

Identify the alpine glacial features indicated by the letter E in the above block diagram

glacial trough

What do we call this "U-shaped valley which was created by an alpine glacier?

glacial trough

Which of the following is NOT a variety of moraine?

hanging

Identify the alpine glacial features indicated by the letter D in the above block diagram

hanging valley

Identify the alpine glacial features indicated by the letter B in the above block diagram.

horn

What is the name used for pyramid-like peaks sculpted by valley glaciers?

horns