1. The Cryosphere Part 2

2. Glacial Topography

3. Movement of Glacial Ice
Snow is the raw material from which glacial ice originates.
Therefore, glaciers form in areas where more snow forms than can melt during the summer.
Glaciers are constantly gaining and losing ice.
Snow accumulation and ice formation occur in the zone of accumulation – here the addition of snow thickens the glacier and promotes movement.
Beyond this area of ice formation is the zone of wastage – here there is a net loss to the glacier when the snow from the previous winter melts, as does some of the glacial ice.

4. Erosional Landforms Created by Alpine Glaciers
Figure 6.10 C

5. Landforms Created by Glacial Erosion
Certain types of special landforms can be created by glacial erosion. These include:
glacial troughs – As a glacier widens, deepens, and straightens a valley, it transforms a v-shaped valley into a u-shaped glacial trough.

6. Landforms Created by Glacial Erosion
Certain types of special landforms can be created by glacial erosion. These include:
hanging valleys – After a glacier has receded, the valleys of tributary glaciers are left standing above the main glacial trough and are termed hanging valleys.

7. Landforms Created by Glacial Erosion
cirques – a bowl-shaped depression at the head of a glacier that was a depression where snow could accumulate, thus starting the formation of the glacier.

8. Landforms Created by Glacial Erosion
tarn - a mountain lake or pool, formed in a cirque excavated by a glacier. It is formed when either rain or river water fills the cirque.

9. Landforms Created by Glacial Erosion
paternoster lake - one of a series of glacial lakes connected by a single stream or a braided stream system. 

10. Landforms Created by Glacial Erosion
arêtes – sharp-edged ridges that are formed when cirques grow and the divide separating them becomes very narrow.

11. Landforms Created by Glacial Erosion
horns – several cirques surrounding a single mountain create the spires of rock called horns.

12. Landforms Created by Glacial Erosion
fiords - glacial troughs that became submerged as the ice left the valley and sea levels rose following the Ice Age

13. Erosional Landforms Created by Alpine Glaciers
Figure 6.10 C

14. Ice Age Glaciers of the Past
An Ice Age began 2 to 3 million years ago during the Pleistocene epoch. During the Ice Age, ice covered 30% of Earth’s land area.

15. Ice Age Glaciers of the Past
Indirect Effects of Ice Age Glaciers As the ice advanced and retreated, animals and plants were forced to migrate. This led to stresses that some organisms could not tolerate.

16. Ice Age Glaciers of the Past
Indirect Effects of Ice Age Glaciers
In areas that were centers of ice accumulation, such as Scandinavia and northern Canada, the land has been slowly rising for the past several thousand years.
The land had downwarped under the tremendous weight of almost 2-mile thick masses of ice.
Following the removal of this immense load, the crust has been adjusting by gradually rebounding upward ever since.

17. Ice Age Glaciers of the Past
Indirect Effects of Ice Age Glaciers
A far-reaching effect of the Ice Age was the worldwide change in sea level that accompanied each advance and retreat of the ice sheets.
The snow that nourishes glaciers ultimately comes from moisture evaporated from the oceans.
Therefore, when the ice sheets increased in size, sea level fell and the shoreline moved seaward.
Estimates suggest that sea level was as much as 330 feet lower than it is today.

18. Ice Age Glaciers of the Past
Indirect Effects of Ice Age Glaciers
The formation and growth of ice sheets was an obvious response to significant changes in climate.
But the existence of the glaciers themselves triggered climatic changes in the regions beyond their margins.
In arid and semiarid areas on all continents, temperatures were lower, which meant evaporation rates were also lower. At the same time, precipitation was moderate.
This cooler, wetter climate resulted in the formation of many lakes called pluvial lakes.
Although most are now gone, a few remnants remain, the largest being Utah’s Great Salt Lake.