Vocabulary Review
Summary of Key Ideas
15.1 Much of Earth’s fresh water is frozen in valley
glaciers or continental glaciers. Glaciers form above the
snow line from compressed snow called firn. The snow
line elevation is high in areas close to the equator and
gets lower in areas farther from the equator.
15.2 Gravity causes glaciers to move. The ice front
of a glacier may advance or retreat depending on
conditions. If a glacier’s ice front is near the sea,
icebergs may break off. As glaciers move, they
erode the underlying surface, leaving behind
characteristic erosional features.
15.3 When glaciers retreat, they leave behind
deposits. Till is unsorted, unstratified material
deposited directly by the ice. Outwash is sorted,
stratified material deposited by meltwater from
the ice.
15.4 Earth has experienced a number of
periods of widespread glaciation. Evidence for
such ice ages comes from erosional and
depositional features. Scientists have
identified a number of possible causes for
glaciation.
Write the term from the key vocabulary list that best
completes each sentence.
1.
?
2. As distance from the equator increases, the
?
elevation of the
decreases.
3. The farthest advance of a glacier is marked by
?
the terminal
4. The rough, granular ice that becomes a glacier is
?
called
.
Explain the difference between each pair of terms.
5. till, outwash
6. valley glacier, continental glacier
7. kame, drumlin
Concept Review
8. How and where do glaciers form?
9. Compare how a glacier moves near its base with
how it moves at its center.
10. Why is the ice front of a glacier not necessarily
stationary?
11. Compare how valley glaciers and continental
glaciers erode materials.
12. In Minnesota, there are many kettle lakes.
Explain how these lakes formed.
13. How is a recessional moraine different from a
terminal moraine?
KEY VOCABULARY
calving (p. 322)
ice cap (p. 320)
cirque (p. 324)
ice front (p. 322)
continental glacier (p. 319)
kame (p. 328)
crevasse (p. 322)
kettle (p. 328)
drumlin (p. 327)
moraine (p. 323)
erratic (p. 327)
outwash (p. 326)
esker (p. 327)
outwash plain (p. 327)
firn (p. 318)
snow line (p. 318)
glacial valley (p. 324)
striations (p. 323)
glacier (p. 318)
till (p. 323)
ice age (p. 330)
valley glacier (p. 319)
14. Describe several possible causes of ice ages.
15. Graphic Organizer Copy and complete the
concept map below using appropriate terms
from the key vocabulary list.
Glacial
deposits
are formed from
?
moraine
336
produces icebergs.
Unit 4 Earth’s Changing Surface
outwash
?
kame
?