GEO CH 18

Today, continental glaciers are limited to Antarctica and ____________. a. Alaska b. Greenland c. Canada d. Siberia

b. Greenland

The effect of periodic changes in Earth's orbital eccentricity and magnitude and direction (precession) of Earth's axial tilt on the advance and retreat of ice sheets was first proposed by ____________. a. Richter b. Milankovitch c. Mohorivic d. Lyell

b. Milankovitch

A bowl-shaped depression formed by a mountain glacier is termed a (an) ____________. a. arête b. cirque c. horn d. tarn

b. cirque

Because glacial advance is driven by gravity, it is impossible for glaciers to advance over perfectly flat terrain. a. true b. false

b. false

Walking across an Antarctic ice sheet during winter would not be very treacherous, because ice is not slippery at temperatures well below freezing. a. true b. false

b. false

By increasing the albedo of Earth, global ice sheets produce conditions that are ____________ to their further advance, thus providing an example of ____________ feedback. a. detrimental; positive b. detrimental; negative c. favorable; positive d. favorable; negative

c. favorable; positive

When sea level rises, causing the ocean to fill a glacially carved valley, a ____________ results. a. smorgasbord b. tarn c. fjord d. ford

c. fjord

Stratified sorted sand and gravel are deposited by ____________. a. mountain glaciers b. continental glaciers c. glacial outwash streams d. wind

c. glacial outwash streams

An angular peak surrounded by three or more bowl-shaped depressions formed by a mountain glacier is termed a (an) ____________. a. arête b. cirque c. horn d. tarn

c. horn

Given the modern continental configuration, it is much easier for large continental ice sheets to become established in the ____________ Hemisphere than in the ____________ Hemisphere. a. eastern; western b. western; eastern c. northern; southern d. southern; northern

c. northern; southern

Ice is a substance with a high albedo, which means it ____________. a. requires much heat to raise its temperature by 1°C b. absorbs most of the light that falls on it c. reflects most of the light that falls on it d. strongly refracts the light that falls on it

c. reflects most of the light that falls on it

A lake that forms within a bowl-shaped depression formed by a mountain glacier is termed a (an) ____________. a. arête b. cirque c. horn d. tarn

d. tarn

Sediments deposited directly by glaciers as they melt are termed ____________. a. firn b. loess c. outwash d. till

d. till

Areas on the southern margins of the continental glaciers of the northern hemisphere were much ____________ during Plio-Pleistocene glaciations than they are today, as suggested by evidence of large ____________ during this time. a. warmer; tropical rainforests b. wetter; tropical rainforests c. drier; deserts d. wetter; pluvial lakes

d. wetter; pluvial lakes

A remnant ridge separating two bowl-shaped depressions formed by a mountain glacier is termed a (an) ____________. a. arête b. cirque c. horn d. tarn

a. arête

Glacial ice exhibits ____________ behavior near the top, but ____________ behavior beneath a depth of 60 m. a. brittle; ductile b. ductile; brittle c. solid; liquid d. plastic; elastic

a. brittle; ductile

An intermediate product in the transformation of snow to glacial ice is ____________. Select one: a. firn b. sublimation c. ablation d. terminus

a. firn

Cirques and horns are features associated with ____________. a. mountain glaciation b. continental glaciation c. glacial outwash deposits d. loess deposits

a. mountain glaciation

A hanging valley is formed when a ____________. a. smaller glacially carved valley intersects a larger glacially carved valley b. smaller stream-cut valley intersects a larger stream-cut valley c. smaller stream-cut valley intersects a larger glacially carved valley d. stream-cut valley is on the upthrust side of a normal fault

a. smaller glacially carved valley intersects a larger glacially carved valley

Although glaciers advanced no farther south than the midwestern states during the Pleistocene, periglacial loess was blown deep into the southeastern states. Select one: a. true b. false

a. true

Question text The current interglacial interval began a little more than ____________ years ago. a. 1,000 b. 10,000 c. 100,000 d. 1 million

b. 10,000

Wind blows finer particles long distances from glacial environments, where they settle out to form ____________. a. firn b. loess c. outwash d. til

b. loess

At the present, glaciers cover about ____________ of the surface of the continents. a. 1% b. 5% c. 10% d. 20%

c. 10%

Valleys carved by glaciers tend to be shaped like the letter ____________, whereas valleys carved by water tend to shaped like the letter ____________. a. V; U b. V; C c. U; V d. V; I

c. U; V

A glacier will always advance from its source area if the rate of accumulation is greater than the rate of ____________. a. subsidence b. melting c. ablation d. abrution

c. ablation

Sediments deposited directly by glaciers as they melt are characterized by ____________. a. uniformly coarse grain size b. uniformly fine grain size c. an absence of sorting d. graded bedding

c. an absence of sorting

An important long-term factor determining whether glacial ice will form on the continents has likely been the proportion of which gas in the atmosphere? a. oxygen b. nitrogen c. carbon dioxide d. carbon monoxide

c. carbon dioxide

Mars has polar ice caps that differ from the Earth's Antarctic ice cap in that ____________. a. the Martian caps consist of a combination of water ice and frozen carbon dioxide (dry ice) b. the Martian caps have a spiral fracture pattern not found in Antarctica c. Martian caps are ablated by sublimation only; there is currently no liquid water on Mars d. All of the above are correct

d. All of the above are correct

The first scientist to theorize the past presence of glaciers in Europe was ____________. a. Isaac Newton b. Charles Darwin c. Walter Alvarez d. Louis Agassiz

d. Louis Agassiz

Cape Cod, Massachusetts, and Long Island, New York, are both examples of Pleistocene glacial ____________ that have been further built up by wave-deposited sands. a. drumlins b. kettles c. eskers d. end moraines

d. end moraines