Practice Questions for Lectures 13
Geology 1200
A. Short answer:
1. A moving body of ice that forms from the accumulation and
compaction of snow is called a ____________.
2. Glaciers flow downslope or outward under the influence of ________.
3. __________ is the packed snow that survives a summer melting
season.
4. __________ glaciers are confined by surrounding mountains
5. __________ glaciers create and occupy semicircular basins on
mountainsides, usually near the heads of valleys.
6. __________ glaciers flow in pre-existing stream valleys.
7. Ice _________ form at the tops of mountains.
8. A _____________ glacier originates as a confined alpine glacier but
flows onto adjacent lowland where, unconfined, it can spread rapidly.
9. A piedmont glacier that reaches seawater is a ____________ glacier.
10.The only completely unconfined glacier is a ____________ ice sheet.
11.In the zone of _________________ more snow is added every year
than is lost.
12.In the zone of _______________ more snow is lost than is added.
13.______________ is the process by which chunks of ice are broken off
by wave or tidal action; it is the source of icebergs.
14.A glacier's _______ is measured by accumulation minus ablation.
15.Although the _______ of a glacier may be advancing, receding, or
remaining stationary, the glacier is always flowing forward.
16.In internal ________________, a glacier's ice crystals deform under
pressure from overlying ice and slip past one another.
18. In __________ sliding, warmer glaciers thaw at their bases,
producing a film of water on which it slides.
B. Match the Terms.
1. Firn _____
a. all glacial deposits
2. Glacier's budget ____
b. seawater floods glacial valley
3. Ablation ____
c. accumulation minus ablation
4. Cirque____
d. makes icebergs
5. Esker ____
e. abrade upglacier, quarry downglacier
6. Till _____
f. semicircular basin on mountainside
7. Drumlins_____
g. loss of snow and ice
8. U-shaped ______
h. dense, well-packed snow
9. Drift ______
i. adjacent glaciers merge
10. Medial moraine ____
j. film of water at base.
11. Calving _____
k. sinuous meltwater deposit under glacier
12. Fjord _______
l. cirque lake
13. Roche Moutonée ____
m. ice sheets override moraines.
14. Basal sliding ______
n. drift deposited directly from glacial ice.
15. Tarn
o. glacial valley shape
_____
C. True or False? Circle the correct answer.
1. Glacial ice carrying coarse rock fragments can cut long striations, or
scratches, into the bedrock surface. These markings are oriented in the
same direction as the ice flow. True or False?
2. Glacial quarrying occurs when a glacier lifts masses of bedrock
dislodged by frost wedging. True or False?
3. Eskers are deep circular alpine basins created by glacial abrasion and
quarrying. True or False?
4. When cirque glaciers melt, a pluvial lake forms in the basin. True or
False?
5. The peak remaining after three or more cirque glaciers erode a
mountain is called a horn. True or False?
6. Valleys carved out by rivers are U-shaped; glaciated valleys are Vshaped. True or False?
7. Hanging valleys result from the faster flow of the main glacier, often
with a tall, beautiful waterfall. True or False?
8. Examples of deep U-shaped troughs formed by continental ice sheets
are the Finger Lakes, Great Lakes, and Loch Ness. True or False?
9. All glacial deposits are called glacial drift. True or False?
10.Drift that is deposited directly by ice is called glacial Till . Till is
unsorted, nonstratified sediment. True or False?
11.An exceptionally large, glacially transported rock is called a glacial
erratic. True or False?
12.If the terminus of a glacier is stationary, a moraine continues to
accumulate at the terminus. True or False?
13.When a glacier recedes for the final time, it leaves a terminal moraine
marking the farthest advance of ice. True or False?
14.Drumlins are gently rounded, elongated hills created by ice sheets
overriding and reshaping moraines. True or False?
15.Meltwater stream sediments are stratified and sorted. True or False?
16.Outwash is deposited downstream of the glacial terminus by braided
streams. True or False?
17.Loess are deposits of silt carried by wind from exposed, drying
outwash. True or False?
18.Sinuous ridges formed beneath the ablation zone are called cirques.
True or False?
19.Near continental ice sheets, ice dams alter drainage patterns. True or
False?
20.Widely contrasting air temperatures near glaciers cause abnormally
cloudy, cool, rainy weather, resulting in pluvial lakes. True or False?
21.Pluvial lakes are landlocked basins in which additional precipitation
accumulates. True or False?
22.The Great Salt Lake is a small remnant of the huge Lake Bonneville, a
pluvial lake which covered much of Utah, eastern Nevada, and
southern Idaho. True or False?
23.Lowered Pleistocene sea levels were due to increased water contained
in glacial ice. This change extended coastlines and exposed land
bridges. True or False?
24.Ice Ages alternate between Glacial periods and Interglacial periods.
True or False?
25.Two requirements for glaciation are sizable landmasses at or near the
poles and land surfaces with relatively high elevation. True or False?
26.The Earth's glacial past is evident from old Tillites, moraines and
eskers, and from glacial striations on bedrock. True or False?
27.The Precambrian had at least three glacial events. True or False?
28.During the Cambro-Ordovician glaciation event the region that is now
the Sahara was over the South Pole. True or False?
29.During the Pennsylvanian and Permian Periods the Gondwana
supercontinent (Australia, Antarctica, India, South America, and South
Africa) was at the South Pole. True or False?
D. Multiple choice:
1) All of the following landforms would be absent without the work of glaciers EXCEPT:
a) the Great Lakes.
b) Niagara Falls.
c) the Rocky Mountains.
d) Cape Cod.
2) Glaciers are classified, in part, by:
a) their rate of growth.
b) their degree of confinement.
c) their size.
d) the rate at which their ice flows.
3) Which of the following statements about glaciers is NOT true?
a) Cirque glaciers create and occupy semicircular basins on mountain sides.
b) Valley glaciers flow in preexisting stream valleys.
c) Continental ice sheets are confined glaciers that move over low-lying continental areas.
d) Piedmont glaciers begin as alpine glaciers but flow onto adjacent lowland.
4) In a confined glacier, the terminus of a glacier advances downslope under which
conditions?
a) Accumulation is greater than ablation.
b) Accumulation is less than ablation.
c) Accumulation and ablation are equal.
d) All of the above.
5) The glacier’s zone of accumulation can be recognized by:
a) icebergs calving into a lake.
b) snow from the previous winter covering the glacier ice.
c) exposed, bare ice.
d) rocks and boulders melting from the ice.
6) Which of the following statements about glacial flow is NOT true?
a) In internal deformation, ice flows because crystals slide past one another under pressure.
b) In basal sliding, a glacier slides along its bed on a film of water.
c) In extremely cold climates, glaciers flow more by basal sliding than by internal
deformation.
7) Glacial surges are caused by:
a) an accumulation of water at the base of the glacier.
b) rapid internal deformation of the ice.
c) a large buildup of snow in the zone of accumulation.
d) the weight of sediment trapped within the glacier.
8) In the alpine highlands of North America, Europe, and Asia, the most effective geologic
shaping process would be:
a) mass-movement.
b) wind erosion.
c) stream erosion.
d) erosion by glaciers.
9) A roche moutonnée can indicate the direction of glacial flow from all of the following
features EXCEPT:
a) its symmetrical sides are parallel to glacial flow.
b) the up-glacial side is usually well striated.
c) the down-glacier side is the most heavily quarried.
d) the up-glacier side is steep and jagged.
10) The difference between a cirque and a tarn is:
a) a cirque is at the zone of accumulation while a tarn is at the zone of ablation.
b) a cirque is a basin made by a glacier while a tarn is a lake within a cirque.
c) a cirque is a basin made by a glacier while a tarn is a mountain pass between two cirques.
d) a tarn is a basin made by a glacier while a cirque is a sharp ridge between two tarns.
11) A submerged U-shaped valley is called a:
a) col.
b) hanging valley.
c) fjord.
d) arête.
12) All of the following landforms were shaped by continental ice sheets EXCEPT:
a) northern Puget Sound of Washington.
b) the mountain peaks of Glacier National Park.
c) the Great Lakes.
d) the Finger Lakes of New York.
13) The term “glacial drift” applies to:
a) all glacial deposits, collectively.
b) glacial deposits of very fine particles that eventually become wind-blown.
c) glacial deposits that are carried by meltwater into nearby streams.
d) the redistribution of glacial deposits by consecutive advances.
14) Till appears different from outwash in that:
a) till contains only smaller particles while outwash contains both small and large rock
fragments.
b) till is darker in color than outwash.
c) till is better sorted and stratified than outwash.
d) till is less sorted and less stratified than outwash.
15) A terminal moraine forms when:
a) accumulation is less than ablation.
b) accumulation is greater than ablation.
c) accumulation and ablation are equal.
d) All of the above.
16) A medial moraine forms:
a) along the sides of a glacier.
b) where two valley glaciers merge.
c) where a glacier terminus advances beyond a recessional moraine.
d) beneath a glacier in a sinuous ridge.
17) Which of the following statements about drumlins is NOT true?
a) Drumlins are elongated, asymmetrical hills.
b) Drumlins are composed of unsorted, unstratified glacial drift.
c) Drumlins are oriented parallel to terminal moraines.
d) Drumlins are formed by continental ice sheets rather than by alpine glaciers.
18) Loess is a soil formed by:
a) meltwater deposits of sand and gravel.
b) glacial advances over previously deposited moraines.
c) a mixture of sand and clay at the bottom of a meltwater lake.
d) wind-blown deposits of outwash silt.
19) During major glaciations, sea level was 130 meters lower than at present, facilitating
land migration between:
a) Africa and South America.
b) Europe and North America.
c) North America and Asia.
d) Asia and Australia.
20) The record of Pliestocene climatic changes is obtained by:
a) studies of the amount of airborne dust in ice cores.
b) 18O/16O ratios in the “shells” of fossil foraminifera.
c) radiometric-geomagnetic-stratigraphic dating of ice cores.
d) observing fossil foraminifera whose coiling direction was dependent on temperature.
e) all of the above.
21) Many geologists have concluded that the development of ice ages requires:
a) large near polar oceans
b) relatively high-elevation landmasses near the equator
c) all of the Earth’s continents to mass together near the equator
d) sizeable landmasses near the poles, and land surfaces with relatively high elevation.
22) The 700 million year old tillite found worldwide indicates an Ice Age extended to the:
a) polar regions.
b) alpine regions.
c) equatorial regions.
d) desert regions.
23) Which of the following describe the most recent extensive glaciation in North America:
a) the ice sheet stretched the full breadth of southern Canada and the northern United States.
b) the ice sheet stripped regolith 15–25 meters deep from regions of Canada and the United
States.
c) a warming began 10,000 years ago.
d) All of the above
24) The “Little Ice Age”:
a) was a period of cooler global temperatures from about 1300 to 1850 A.D. and included
glacial expansion in mid-latitude mountain ranges.
b) was the last major Pleistocene episode of glaciation, and ended about 10,000 years ago.
c) refers to the present Quaternary ice age, which, in geologic terms, has been shorter than
many of the Earth’s earlier ice ages.
d) was the Earth’s first known ice age, and occurred during the Precambrian Era.
25) For approximately the last 150 years, the Earth’s average global temperature has:
a) alternated between warming and cooling.
b) remained relatively constant.
c) decreased.
d) increased.
Short Answer (Answer both)
1. How does plate tectonics contribute to the initiation of an ice age?
2. How do changes in Earth’s orbit contribute to the initiation of an ice age?