Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
31 Cards in this Set
- Front
- Back
|
valley/alpine glaciers
|
advance slowly
|
|
|
ice sheets
|
exist on a larger scale, flow out in all directions
|
|
|
ice shelves
|
-occur when glacial ice flows into the adjacent ocean
-large, flat masses that extend seaward -thickest on landward side |
|
|
ice caps
|
-cover uplands and plateaus
|
|
|
outlet glaciers
|
-tongues of ice that flow down valleys extending outward
|
|
|
Piedmont glaciers
|
-occupy broad lowlands at the bases of steep mountains and form when one or more alpine glaciers emerge fromt he confining walls of mountain tops
|
|
|
firn
|
-the recrystallization of snow
|
|
|
flow
|
-the movement of glacial ice
|
|
|
two types of glacial ice
|
1. plastic flow- movement within ice
2. basal slip- when entire ice mass slips along the ground |
|
|
Zone of fracture
|
ice in uppermost zone, brittle
|
|
|
Crevasses
|
-cracks caused when the glacier moves in irregular terrain
|
|
|
surges
|
periods of rapid movement
|
|
|
Where do glaciers move the most?
|
-in areas where more snow falls in the winter then melts during the summer
|
|
|
zone of accumulation
|
-where snow accumulation and ice formation occur
|
|
|
snowline
|
-outer limits of zone accumulation
|
|
|
calving
|
-when large pieces of ice break off in front of the glacier-creates icebergs
|
|
|
glacier budget
|
-balance or lack therof between accumulation of upper end and loss at lower end
|
|
|
When are glaciers stationary?
|
-when ice accumulation excedes ablation and glacier front advances until the two factors balance
|
|
|
When does a glacier retreat?
|
-if a warming trend increases ablation and/or if a drop in snowfall decreases accumulation
|
|
|
ablation
|
loss at lower end of glacier
|
|
|
rock flour
|
-pulverized rock produced by glacial "grist mill"
|
|
|
glacial striations
|
-scratches and grooves in glaciers
|
|
|
glacial trough
|
-U shaped (wide and deep)
|
|
|
hanging valleys
|
-when glaciers recede, valleys of tributary glaciers are left standing above the main glacial trough
|
|
|
pater noster lakes
|
-when depressions on valley floor are filled with water
|
|
|
cirque
|
-bowl shaped depression with walls on three sides
|
|
|
fiords
|
-deep, steep sided inlets of the sea, present at high altitudes
|
|
|
aretes
|
-sharp edged ridges, come from enlargement of cirques
|
|
|
roche moutonee
|
-an asymmetrical knob of bedrock, formed when glacial abrasion smoothes gentle slope and plucking steepens the opposite side
|
|
|
How do glaciers form?
|
-from accumulating ice that gradually turns into snow
|
|
|
ice plucking
|
-when rock and debris get frozen onto the ice and pulled up
|
