Deck 17: Glaciers and Glaciation

Question 1

The "Great Ice Age"glaciers were most extensive and active in the Northern Hemisphere.

Answer 1

True

Question 2

Glaciers are geologically important because they erode , transport, and deposit so much material in such a relatively short period of geologic time.

Answer 2

True

Question 3

The glacial budget controls the advance and retreat of both valley and continental glaciers.

Answer 3

True

Question 4

Glaciers flow under their own weight.

Question 5

Sublimation is the loss of water by melting and infiltration at the base of the glacier TrueFalse

Question 6

In contrast to running water, flowing ice is generally laminar.

Question 7

Glacial ice is brittle at thicknesses less than approximately 40 meters.

Question 8

Glaciers flow when accumulation of ice is greater than ablation.

Question 9

The vast expanse of the Pleistocene glaciers and the limited extent of valley glaciers show that continental glaciers and ice caps flow more rapidly than valley glaciers.

Question 10

Glaciers erode bedrock because the ice is so thick and under tremendous pressure.

Question 11

Plucking is an erosional process that occurs due to melting and refreezing of meltwater in rock fractures.

Question 12

U-trough valleys are characteristic of continental glaciers.

Question 13

For valley glaciers, the cirque is the zone of accumulation.

Question 14

Glacial drift refers to the poorly-sorted and unstratified sediment rafted by continental and valley glaciers.

Question 15

The difference between glacial till and outwash is the removal of the fine fraction by running water.

Question 16

Moraines are formed from outwash bulldozed by the glacier along its terminus.

Question 17

Kames and eskers are composed of till, hydrodynamically shaped by glacial ice and meltwater.

Question 18

The Great Lakes were even greater (larger) prior to Pleistocene glaciation.

Question 19

During the Pleistocene, the semiarid and arid areas of the western U.S. contained large proglacial lakes.

Question 20

Isostatic rebound occurs because glacial ice causes Earth's crust to deform.

Question 21

According to the Milankovitch theory, small irregularities in Earth's rotation and orbit were sufficient to caused Pleistocene glaciation.

Question 22

During an Ice Age, which of the following occur?

A) warm, dry climates outside the glaciated area are more humid and cool
B) continental and valley glaciers advance
C) sea level is lowered
D) B and C
E) all of the above

Question 23

Glaciers exist at

A) high latitudes and/or high altitudes
B) high latitudes and/or low altitudes
C) low latitudes and/or high altitudes
D) low latitudes and/or low altitudes

Question 24

Which of the following erosional landforms would be found in the zone of accumulation of a valley glacier?

A) cirques, aretes, and eskers
B) cirques, eskers, and moraines
C) cirques, aretes, and horns
D) aretes, horns, and moraines
E) cirques, horns, and moraines

Question 25

Which of the following deposits or depositional landforms might generally be found along the terminus of a valley glacier?

A) u-shaped trough, terminal and recessional moraines, outwash
B) terminal and recessional moraines, kettles, hanging valleys
C) roche moutonnée, terminal and recessional moraines, outwash
D) striations, eskers, outwash
E) terminal and recessional moraines, outwash, till

Question 26

Glaciers move by

A) plastic flow
B) basal slip
C) surge
D) A and B
E) all of the above

Question 27

Stagnant glaciers result from which of the following set of conditions?

A) accumulation equals wastage
B) accumulation is less than wastage
C) accumulation is greater than wastage

Question 28

Glaciers advance under which of the following set of conditions?

A) accumulation equals wastage
B) accumulation is less than wastage
C) accumulation is greater than wastage
D) none of the above

Question 29

Glaciologists believe a glacial surge might be enhanced

A) plastic flow following periods of unusually heavy snowfall
B) basal slip due to increased slope of the glacier
C) by rapid melting along the base of the ice
D) A and B
E) all of the above

Question 30

Glacial erosion occurs

A) only in the zone of accumulation
B) in the zone of accumulation and the zone of wastage
C) only in the zone of wastage
D) in the zone of wastage and in the proglacial area
E) only in the proglacial area

Question 31

The primary difference between valley glaciers and continental ice sheets is that

A) the ice sheets do not flow
B) the valley glaciers form at high altitudes while the ice sheets form at high latitudes
C) the valley glaciers form in warm periods as well as cold periods
D) the ice sheets initially develop at the poles and valley glaciers can develop in any mountain chain
E) ice sheets are larger than valley glaciers

Question 32

The visually most-striking features of glaciation by most people's standards would be viewed in

A) the zone of accumulation of continental ice sheets
B) the zone of accumulation of valley glaciers
C) the zone of wastage of continental ice sheets
D) the zone of wastage of valley glaciers
E) A and B

Question 33

Which of the following combinations of depositional landforms would be formed from glacial till?

A) all moraines, eskers, and kames
B) eskers and kames, outwash plains, and valley trains
C) end moraines, medial and lateral moraines, and drumlins
D) all moraines, drumlins, and valley trains

Question 34

Which of the following combinations of depositional landforms would be formed from glacial outwash?

A) all moraines, eskers, and kames
B) eskers and kames, outwash plains, and valley trains
C) end moraines, medial and lateral moraines, and drumlins
D) all moraines, drumlins, and valley trains

Question 35

Regions adjacent to the glacial terminus in North America had a climate which was/had:

A) very cold year-round
B) cold and dry year-round
C) cool, wet winters and short summers
D) dry, cool winters and short wet summers
E) moderate year-round.

Question 36

Milankovitch theory proposes that the glacial-interglacial cycles of the Pleistocene was NOT the result of

A) orbital eccentricity
B) precession of the equinoxes
C) changes in axial tilt
D) sun spot activity
E) irregularities in earth's orbit

Question 37

Short-term climatic events such as the Little Ice Age may result from

A) a combination of one or more factors in the Milankovitch theory
B) anomalous tectonic plate configurations
C) variations in solar energy
D) sun spot activity
E) large volcanic eruptions

Question 38

In general, rates of glacial flow are greatest in the zone of (accumulation, wastage)___________.

Question 39

The climatic event which, among other things, ended the Viking colonization of Greenland is known as the___________ ___________ ___________ .

Question 40

___________ ___________ of a glacier is facilitated by the presence of___________, which reduces basal friction.

Question 41

A glacier will begin to flow when the ice reaches a critical thickness of___________ meters.

Question 42

A glacier advances when ___________exceeds ___________.

Question 43

Is the basic process responsible for advance of valley glaciers the same as for advance of continental glaciers?

Question 44

Briefly explain how continental glaciers can flow uphill.

Question 45

What is a stagnant glacier? Why does a glacier become stagnant?

Question 46

What were two of the geological consequences of the 130 m drop in sea level which occurred during the maximum glacial coverage of the Great Ice Age?

Question 47

During recession, does ice flow towards the terminus or back towards the zone of accumulation? Explain.

Question 48

What is a glacier?

Question 49

Approximately what percentage of Earth's surface do glaciers presently cover?

Question 50

Where is the largest existing glacier located?

Question 51

When were the present glacial landscapes mainly formed?

Question 52

Can glaciers occur in the equatorial latitudes? Explain your

Question 53

What is the process of sublimation?

Question 54

How does firn form?

Question 55

If glacial ice is a rock, in which of the three rock families could it best be classified? Why?

Question 56

What are the two basic types of glaciers recognized by geologists?

Question 57

Where do continental glaciers presently exist?

Question 58

Where might you find some present examples of ice caps?

Question 59

What is the terminus of a glacier?

Question 60

What is a surging glacier?

Question 61

Why is predicting glacial surges considered important?

Question 62

What are glacial erratics?

Question 63

What is a roche moutonnée?

Question 64

What are the principle ways by which glaciers erode the surface over which they flow?

Question 65

Where does a cirque form?

Question 66

What is rock flour?

Question 67

What kind of glacial erosional landform is the Matterhorn in Switzerland?

Question 68

What is a tarn?

Question 69

What is glacial drift?

Question 70

What is glacial till?

Question 71

Name four different types of moraines.

Question 72

What are drumlins?

Question 73

What are glacial varves?

Question 74

Name the geologist who first convincingly argued that widespread glaciation of the northern hemisphere could explain many geological deposits of Pleistocene age.

Question 75

What is the significance of a dropstone found embedded in varves?

Question 76

Based on evidence from deep-sea cores, there have been at least how many warm-cold cycles since the beginning of the Pleistocene glaciation?

Question 77

How long ago did glacial conditions really begin, with cooling of Southern Hemisphere surface waters?

Question 78

By how long ago had a continuous ice sheet formed in Antarctica?

Question 79

When did ice sheets finally begin forming in the Northern Hemisphere?

Question 80

How did the overall world climate during glacial advances of the Great Ice Age compare to today's climate?