Glaciers Flashcards
1
Q
Glacier:
A
- Mass movement of frozen ice on land
- Form at high latitude or high elevation
- Last extension of ice here began 20,000 years and receded about 10,000 years ago
- Today only covers 10% of land surface
2
Q
Ice Flow:
A
Glaciers are not static, they are dynamic
3
Q
Formation:
A
- A stead accumulation of snow piles up and compresses layers beneath,, these compressed layers turn into ice
- Force of gravity continuously pulls ice downward
- Firn
4
Q
Movement:
A
- Fastest ice is found on the surface at the center of the valley
- Rate varies from a few cm to meters per day
5
Q
Three categories of glaciers:
A
- Valley (alpine) glaciers
- Ice sheets (continental glaciers)
- Tidewater glacier
6
Q
Valley (alpine):
A
- Found in mountainous regions
- High altitude
- Alps, Rockies
7
Q
Ice Sheets (continental glaciers):
A
- Much larger
- Flow direction is form and area of thick ice to thin ice
- Greenland, Antarctica
8
Q
Tidewater glacier:
A
- Flow far enough to reach out into ocean
- Create icebergs
9
Q
Glacier accumulation:
A
Snow adds to weight of a glacier
10
Q
Glacier wastage (ablation):
A
- Breaking of ice forming icebergs
- Melting and calving
11
Q
Accumulation is greater than wastage:
A
Glacier advances
12
Q
Accumulation is less than wastage:
A
Glacier retreats
13
Q
Accumulation = wastage:
A
Glacier remains stationary
14
Q
Glacial erosion & features:
A
- Plucking and abrasion
- U-shaped valleys, sharp ridges (Aretes), pyramid peaks (horns), water filled valleys (Fjords = hudson river) and bowl shaped valleys (cirques)
15
Q
Deposition features:
A
- Drift
- Stratified Drift
- Till
