Geography Chapter 19

Front 1

Describe the extent of modern glaciation

Back 1

-very limited
-10% of land surface

Front 2

In what state is the largest glacier in the US? Where are the two largest continental ice sheets? How much of the world’s land ice do these 2 ice sheets contain? Which is larger?

Back 2

-Bering Glacier in Alaska is the largest
-Antartica is the largest on Earth, Greenland is 2nd
-96% of world's ice

Front 3

During the most recent period, how long has the Earth been “deglaciating”?

Back 3

-Antartica has been melting .22* for 50 years
- Global warming for 30 years

Front 4

Cirque

Back 4

-amphitheater-like valley head
-formed at the head of a valley glacier by erosion
-Hollowed out and when melts can hold water
-steep and perpendicular
-this is where an alpine glacier began

Front 5

Arête

Back 5

-thin, knife-like rock, "fish bone"
-formed when 2 glaciers erode parallel u-shaped valleys
-is a all that is left of a ridge crest after lots of glacial cirque have been cut back into interfluve from opposite sides of a divide

Front 6

Roche moutonnee

Back 6

-rock hill shaped by the passage of ice "sheared off"
-the stoss side has had glacial scouring, and gives it a polished smooth look
-lee side has had glacial plucking, and gives it a jagged steep side

Front 7

Describe the three types of alpine glaciers

Back 7

1. Cirques
2. Arétes
3. Horns

Front 8

Horns

Back 8

-pyramid-shaped mountain peaks
-formed by quarrying of headwalls
-3 or more cirques intersect
-example: Switzerland's Matterhorn

Front 9

Continental ice sheets

Back 9

-found in non mountainous areas
-greatest across land surfaces
-Antartica and Greenland
-Great depths interior, thin around edges
-they tend to move

Front 10

Mountain glaciers (alpine)

Back 10

-confined to mountain and valleys
-do not reshape the terrain like continental ice sheets
-erosion reshapes peaks and valleys
-do not move
-Pleistocene

Front 11

Describe the metamorphosis from snow to glacial ice

Back 11

-Starts with year-to-year snow accumulation
-snow that falls in winter is greater than what melts away in summer
-snow keeps weighing down the old snow and turns into ice
-soon the ice mass begins to move due to gravity
-depends on snow accumulation and ablation

Front 12

Nèvè

Back 12

-snow granules that are packed and coalesce due to compression
-density is half of that of water
-aka Firn

Front 13

Discuss the mechanisms of glacial movement.

Back 13

-plastic flow
-basal slip

Front 14

Plastic flow of ice

Back 14

-slow, non-brittle flow and movement of ice under pressure

Front 15

Basal slip

Back 15

-the sliding of the bottom of a glacier over its bed on a lubricating film of water

Front 16

How are kettle holes formed?

Back 16

-ice blocks get broken off a glacier
-the ice is then mixed with glacier debris and outwash
-the ice will melt slowly leaving behind holes or depressions
-Kettles can be responsible for lakes

Front 17

How are eskers formed?

Back 17

-streams flowing through tunnels inside of an ice sheet becomes clogged because ice wasn't flowing, advancing, and debris

Front 18

How is sea level affected during “Ice Ages”?

Back 18

-sea levels dropped
-Frozen water accumulates on land, reducing water in the oceans

Front 19

Accumulation zone

Back 19

-the upper part of a glacier
-there is more annual accumulation of ice than there is wastage

Front 20

Ablation zone

Back 20

-the lower part of a glacier
-there is a loss of ice due to melting and sublimation

Front 21

Equilibrium line

Back 21

-a line separating the ablation and the accumulation zone of a glacier
-Accumulation exactly balances ablation

Front 22

How fast do glaciers typically move in a day?

Back 22

-Anywhere from a few centimeters to 100ft a day
-fast moving ice is at the surface
-slow moving ice is in depth

Front 23

Erratic

Back 23

-a piece of rock that differs from the size and type of rock native to the area in which it rests

Front 24

Till

Back 24

-rock debris that is deposited by moving or melting ice
-no meltwater flow or redeposit involved

Front 25

Drift

Back 25

-All material carried and deposited by glaciers

Front 26

Terminal moraine formation

Back 26

-is formed when a glacier reaches its equilibrium point
-it is wasting at the same tae that its begin nourished
-outermost edge

Front 27

Recessional moraine formation

Back 27

-created during temporary halts in a glacier's retreat
-behind the outermost edge

Front 28

Lateral moraine formation

Back 28

-formed from ridges of till on the sides of a glacier
-parallel to the valley walls

Front 29

Medial moraine formation

Back 29

-formed when two glaciers merge
-lateral moraines come together to form a single moraine

Front 30

Describe the effects that glaciers have on the terrain

Back 30

-Significantly reshape the topography
-moving ice grinds away almost anything in its path

Front 31

How do continental ice sheets differ from alpine glaciers in the way that they affect the terrain?

Back 31

-ice sheets reshaped the terrain and drainage of nearly one-fifth of Earth's land surface
-Alpine erode mountains and create slopes steeper and relief than what was there before

Front 32

Ground moraine formation

Back 32

-Rolling-to-flat landscapes that form under the ice sheet
-aka till plain

Front 33

Nunataks

Back 33

- isolated peak of rock projecting above a surface of inland ice or snow
-form by Mountain glaciers accumulate sufficiently to isolate and surround a mountain peak

Front 34

Outwash plain

Back 34

-large areas of glacial sediment dropped by meltwater streams furthest away from the glacial snout
-mostly sand and gravel

Front 35

Piedmont glaciers

Back 35

-valley glaciers that have spilled out onto flat plains, where they spread out into bulb-like lobes
-Malaspina Glacier in Alaska

Front 36

Valley glacier

Back 36

-provide drainage for ice fields
-river of ice
-spills out of its original basin and flows down valley

Front 37

What are the types of mountain glaciers, and how are they related?

Back 37

-A cirque glacier can become a valley glacier and then a piedmont glacier

Front 38

Where do glaciers form?

Back 38

-in places where more snow falls in the winter than melts away in the summer

Front 39

What is the snow line?

Back 39

-the elevation above which snow persists throughout the year

Front 40

What is the zone of wastage?

Back 40

-the part of a glacier where snow melting exceeds snow accumulation

Front 41

Under what conditions will the front of a glacier remain stationary?

Back 41

-Glacial fronts remain stationary when melting and snow accumulation are equal.

Front 42

What is an end moraine?

Back 42

-a ridge of debris deposited at the end of a glacier

Front 43

How does an end moraine form?

Back 43

-Pieces of rock are transported to the front of a glacier as ice within the glacier moves.

Front 44

Will plucking occur if a glacier is not advancing?

Back 44

-Yes, because glacial ice is still moving inside the glacier even if the glacier’s front is not advancing.

Front 45

What is the impact on a glacier in a year when melting exceeds snowfall?

Back 45

-The area of the glacier shrinks

Front 46

What is the ocean-filled portion of a previously glaciated valley called?

Back 46

- Fjord

Front 47

Which glacial landform can be found beyond the extent of the ice?

Back 47

-Outwash plain