Deck 14: Glaciers and Glaciation

Question 1

Is ice a mineral? Explain.

Answer 1

Yes,ice is a mineral.It is a naturally-occurring,inorganic substance with a distinct chemical composition and physical structure.

Question 2

What are dropstones,and what do they indicate?

Answer 2

Dropstones are gravel- to boulder-sized rocks found in otherwise fine-grained glacial lake deposits.They indicate transport of the rocks into the lake by icebergs that eventually melted,releasing the coarser sediment.

Question 3

What are eskers and how do they form?

Answer 3

Eskers are long,sinuous ridges of stratified drift.They form in tunnels beneath stagnant ice and in meltwater channels on the surface of glaciers.

Question 4

Under what conditions can glaciers exist in the equatorial latitudes?

Question 5

Explain how medial moraines develop.

Question 6

How does the water bound in glaciers eventually re-enter the hydrologic cycle?

Question 7

Explain the origin of varves and their significance in the chronologies of glacial lake deposits.

Question 8

How does a fiord form?

Question 9

Briefly explain the origin of drumlins.

Question 10

How does the Milankovitch theory explain intermediate-term climatic events like the Pleistocene glaciation? According to Milankovitch,variations in what three parameters of Earth's orbit were responsible for the onset of Pleistocene glaciation?

Question 11

From the human perspective,what climatic effect of the Little Ice Age had the greatest impact?

Question 12

The climatic event that began with cooling in about AD 1300 and lasted until the middle 1800s is known as the Little ____________________.

Question 13

An ice mass of compacted and recrystallized snow that flows under its own weight on land is called a(n)____________________.

Question 14

Briefly explain how a hanging valley forms.

Question 15

What is a possible explanation for long-term variations in Earth's climate?

Question 16

Why do scientists study glaciers to better understand climate change? What do studies of glaciers contribute to our understanding of current climate trends?

Question 17

What are some of the characteristics of large ice-scoured plains,such as those of the Canadian Shield region?

Question 18

Why do continental glaciers generally flow more slowly than valley glaciers?

Question 19

How can the boundary between the zones of accumulation and wastage on a glacier be located during the spring and summer?

Question 20

Name some erosional landforms that might help you recognize that a valley had previously been occupied by a valley glacier.

Question 21

The fine,clay- and silt-sized particles that result from glacial pulverization of rock is known as ____________________.

Question 22

The presence of ____________________ in the upper 40 m or so of a glacier indicates that this portion behaves not as a plastic,but as a(n)____________________ solid.

Question 23

Finely laminated,alternating light and dark layers of sediment deposited in a glacial lake are known as glacial ____________________.

Question 24

Glaciers move primarily by ____________________ flow.

Question 25

The zone of ____________________ is the portion of a glacier where additions exceed losses.

Question 26

The present glacial landscapes mainly formed during the ____________________ Epoch,which lasted from ____________________ years to ____________________ years ago.

Question 27

Where is the largest existing glacier located?

A) Greenland
B) Alaska
C) The Alps
D) Patagonia
E) Antarctica

Question 28

In the process of sublimation

A) ice melts to become liquid water, which then evaporates.
B) fresh snow becomes firn and then glacial ice.
C) ice changes directly into water vapor.
D) white ice becomes denser so that blue wavelengths are transmitted and scattered and the ice appears blue.

Question 29

The three stages involved in the formation of a glacier are the precipitation of ____________________; the formation of ____________________ by partial thawing,refreezing,and crystallization; and compaction and recrystallization to produce ____________________.

Question 30

The distal end or edge of the glacier is called its ____________________.

Question 31

The Matterhorn in Switzerland is a glacial ____________________ landform known as a(n)____________________.

Question 32

The zone of wastage is the portion of a glacier where ____________________ exceed ____________________.

Question 33

When snow thaws and refreezes,which results in a loss of air and pore spaces,the result is ____________________.

Question 34

In general,rates of glacial flow are greatest in the zone of ____________________.

Question 35

Any sediment deposited as a result of glacial activity is known as glacial ____________________.

Question 36

A glacier that is now longer flowing is called a(n)____________________ glacier.

Question 37

Which is the only continent that does not presently have glaciers?

A) South America
B) North America
C) Africa
D) Europe
E) Australia

Question 38

When did the Pleistocene Ice Age end?

A) 1.8 million years ago
B) 10,000 years ago
C) 1,300 years ago
D) 200 years ago
E) It still hasn't ended.

Question 39

A glacier that is unconfined by topography and has tributaries is a

A) ice cap.
B) tributary glacier.
C) continental glacier.
D) valley glacier.

Question 40

The two major types of glaciers are ____________________ and ____________________.

Question 41

Ice Ages

A) have been common through Earth history.
B) have glacial episodes separated by very short interglacial stages.
C) are caused primarily by plate tectonics.
D) are the result of variations in the amount of solar heat received.

Question 42

If glacial ice were a rock it would be a(n)_______ rock.

A) igneous
B) sedimentary
C) metamorphic
D) glacial ice cannot be a rock

Question 43

Glaciers are geologically important because they erode,transport,and deposit so much material.

Question 44

Earth's orbit varies from nearly circular to more elliptical in a roughly 100,000-year cycle.

Question 45

A steep-walled,pyramidal peak formed by headward erosion of cirques.

Question 46

A strong correlation has been established between periods of intense volcanism and short-term glacial cooling.

Question 47

The Little Ice Age ended in the mid to late 1800s.

Question 48

A glacier begins to flow when the ice reaches what critical thickness?

A) 100 meters
B) 40 meters
C) 20 meters
D) 10 meters
E) 5 meters

Question 49

A conical hill of stratified drift is an esker.

Question 50

In a cross-section of a glacier,where do the greatest flow velocities occur?

A) at the surface
B) in the few tens of meters below the surface
C) in the few tens of meters above the base
D) at the base
E) in the center of the flow

Question 51

Valleys carved by glaciers are distinctive because they are V-shaped in cross-section.

Question 52

A glaciers budget is balanced when

A) additions to the zone of accumulation equal losses in the zone of wastage.
B) losses in the zone of accumulation equal additions to the zone of wastage.
C) the zone of accumulation receives more input than the zone of wastage.
D) the zone of wastage does not lose material.

Question 53

Glacial till is ____.

A) any sediment deposited as a result of glacial activity
B) boulders transported long distances and deposited by glaciers
C) an elongated spoon-shaped hill that has been shaped by an overriding glacier
D) unstratified sediment deposited directly by a glacier
E) a lake within an outwash plain.

Question 54

Basal slip becomes a more important means of glacier movement in warmer months when more meltwater collects at a glacier's base.

Question 55

A glacial landform produced primarily by plucking rocks on the downstream side and smoothing by the glacier on the upstream side is called a(n)____.

A) roche moutonnée
B) esker
C) kame
D) terminal moraine
E) cirque

Question 56

Straight scratches on rock surfaces created by glacial abrasion are known as what?

A) rock flour
B) glacial striations
C) glacial till
D) varves
E) moraines

Question 57

A glacial landform that forms at the head of glacial valleys or troughs is called a(n)____.

A) roche moutonnée
B) esker
C) kame
D) arête
E) cirque

Question 58

There is good evidence that variation in solar energy,as evinced by sunspot activity cycles,is responsible for short-term climatic variations.

Question 59

What is a lake formed within a cirque called?

A) arête
B) esker
C) tarn
D) fjord
E) drumlin

Question 60

End moraines continue to grow as long as the ice front remains stationary.

Question 61

The decade from 2000 to 2009 was the hottest on record so far.