Chapter 4

Appoximately how much of Earth;s land surface is currently covered by glaciers?

10%

In order to flow plastically, glacial ice must be under the equivalent pressure of approximately ____ feet of ice above it.

165 ft

Dry lands encompass approximately ___ of Earth's land surface.

30%

During the last Ice Age, continental ice sheets and other glaciers covered approximately ___% of Earth's land areas.

30%

A sheet-like glacial mass that spreads across a broad flat plain beneath the outlet of a large valley glacier is known as a(n)________

?

For the terminus of a glacier to advance, there must be more _____?

?

The terminus of a glacier will retreat if there is

?

The cone of coarse grained sediments that is deposited when ephemeral desert streams exit from stepp mountain canyons out into a wide, flat, valley is called a(n) _____.

Alluvial Fan

Glaciers that form in the high mountains are often referred to as ____ glaciers?

Alpine

A knife edge ridge created by glacial erosion on either side is called a(n) _______?

Arete

A dry stream bed found in dry areas of the western United States is often referred to as a ____?

Arroyo & Wash

The head (top) of a glacially carved valley is known as a(n) ______?

Cirque

_______ are large cracks which open up in the uppermost brittle part of a glacier?

Crevasses

The pattern of sloping layers created by movement of sand grains from one side of a dune to another (which may be preserved in the sedimentary deposit or in lithified sedimentary rock) are called ______.

Cross Beds

Blowouts and desert pavement are both created by a from of wind erosion known as ____?

Deflation

There are two types of "dry climate types: deserts and steppes. Which climate type is technically more dry than the other?

Desert

Glacial ______ refers to any type of sedimeny of glacial origin, regardless of location, texture, or mechanism of deposition.

Drift

A mound of glacial sediments deposited at the terminus of a glacier that is niether advancing nor retreating is called a _____?

End Moraine

A stream which only flows during periods of heavy rainfall is described as being _______?

Ephemeral

A sinuous ridge of stratified drift made up mainly of sand and gravel that was deposited by glacial meltwater in a tunnel beneath an ice sheet is known as a(n) _____?

Esker

A retreating glacier will flow uphill, T/F?

False

Because deserts are so dry, most of the erosional work that occurs is done by blowing wind, T/F?

False

Even though wind cannot pick up and transport coarse grained materials as well running water can, it is still the most significant force of erosion and deposition in desert enviorments, T/F?

False

Scientific studies have shown that the last Ice Age was a period of time that began between 2 and 3 million years ago and involved a single rapid advance of glacial ice sheets worldwide followed by a strady retreat until today. T/F?

False

A glacial trough that has been submerged by rising sea leveles following an ice age is called a(n) _____?

Fiord

Above the depth where plastic flow dominates, ice behaves as a brittle soild material in what is known as the zone of ____________?

Fracture

Bedrock surfaces that are straited and/or polished are clear indications of ________?

Glacial abrasion

Glaciers are considerd to be apart of two of Earth's basic cycles: the hydrologic cycle and the rock cycle. Why are glaciers apart of both cycles?

Glaciers are apart of the rock cycle becuase they are responsible for eroding, collecting, transporting and depositing sediment. Glaciers are part of of the hydrologic cycle becuase they are a step between the formation of precipitation in the atmosphere and the point where liquid water reenters the ocean.

A surface layer of gently rolling till left behind a retreating glacier is referred to as a(n)_____?

Ground Moraine

When a smaller glacier calley intersects the main truck of a much bigger and deeper glacier trough the resulting landform that is formed is known as a ____ valley?

Hanging

The vast majority of Greenland is covered by an enourmous glacier that is very thick and covers many hundreds of thousands of square miles of land. This type of glacier is known as a(n) _______

Ice sheet

Few of the drainage basins found within the Basin & Range actually ever flow all the way to the ocean. Becuase of this we characterize these regions as having _____?

Interior Drainage

A _______ is a water filled glacial basin or depression formed when blocks of glacial ice break off a retreating glacier and become buried in glacial drift.

Kettle

The mounds of glacial sediments pushed out to the sides of an advancing glacier and left behind after the glacier recedes are called_____?

Lateral Moraines

Large deposits of windblown silt are referred to as _____?

Loess

According to glacial flow experiments first conducted in Switzerland beteween 1874 and 1882, researchers were able to show that an alpine glacier flows fastest near the ______?

Near the center

A shallow, dry lake bed formed by deposition of sediments from seasonal flow into an isolated drainage basin is called a _____?

Playa

The process by which a glacier erodes a land surface by loosening and lifting blocks out of a fractured bedrock surface is known as_____?

Plucking

During the peak of the last Ice Age, the cooler global climate generated much more rainfall over what is now mostly deserts across Nevada and Utah. The numerous lakes that once occupied these regions are referred to as _____ lakes becuase they were fed by the increased rainfall during that time period.

Pluvial

Climatologist define a dry climate as one in which yearly ____ is less than the total yearly loss of water by ______

Precipitation; evaporation

Middle latitude deserts like those found acorss the Basin & Range of North America are created because high mountaind like the Sierra Nevada and Cascades act as a barrier to storm systems and strip them of moisture before they reach the lands of the leeward side. These types of deserts are said to be in the ______ of these mountain ranges.

Rainshadow

The steep side of an asymmetrically shaped sand dune is known as the ______?

Slip Face

What is untrue about glaciers?

Some glacial ice is formed from water that freezes on the open oceans in polar regions like the North Pole.

Deposits of ______ are sorted glacial sediments depositied by glacal meltwater.

Stratified Drift (Has Layers)

Big desert regions like the Sahara in North Africa and the Great Sandy desert in Austrailla are the product of global air circulation that create high pressure that warm and dry the air across these regions. These circulatory pressure systems are known as ______

Sub tropical highs ?

Glacial _______ consits of a characteristically unsorted mixture of rock, sand, and silt depositied directly by melting glacial ice.

Till

Glaciers can also flow by sliding along the ground at their base, T/F?

True

Many of the landscapes we see today (such as Yosemite Valley) were shaped by glaciers that were active during the most recent Ice Age, T/F?

True

Valley glaciers can appear to flow in branching patterns with smaller tributary glaciers feeding into larger trunk glaciers much like the dendtric pattern of a rivewr drainage system, T/F?

True

Alpine valleys that have been shaped by the combined erosive forces of running water and mass wasting will typically have a _____-shaped profile?

V;U

Sand dunes are often asymmetrically shaped due to the direction of the prevailling winds. In this situation, the sand grains are being moved and/or eroded from the _______ side and deposited over the dune crest on the _____ side.

Windward; Leeward

The portion of a glacier where more snow and ice melts during the summer than what accumulates in the winter is called the ______?

Zone of Wastage

The portion of a glacier where more snow falls in winter than melts away during the summer is called the _______?

Zone of accumulation

During the peak of the last Ice Age, global sea levels were:

much lower than they are today (330 ft or 100 meters lower)