Glaciers
Contrast alpine and continental glaciers.
-alpine: formed at the top of mountains, flow downhill, tend to be small, make topography more intense -continental: formed at the poles, flow towards the equator, huge, flatten topography
Evidence for glaciers?
-grooves (indents) -polished rocks -chatter rocks (divots)
Contrast river cut terrain with glacier cut terrain.
-river cut terrain: v-shaped valleys - glaciers cut terrain: u-shaped valleys, glaciers make valleys deeper (steep walls)
Contrast river deposits with glacial deposits.
-river deposits: rocks are sorted, rocks are generally rounder -glacial deposits: rocks are unsorted, rocks are more angular
Features of glacial deposits?
-unsorted rocks -rocks are angular -moraine
Contrast a drumlin with a kettle.
A drumlin is a hill (build up) and a kettle is an indentation. Both are depositional features.
Contrast a lateral moraine and an arete.
Both formed on the side; lateral moraine is a deposit formed by one glacier, an arete is the bedrock that was left behind by two parallel glaciers.
Why do glaciers move? How do glaciers move?
Glaciers move because there are many layers of a glacier, and once the solid ice has become compressed enough, it turns into a flowy solid. This flowy solid is called plastic flow, and causes basal slipping of the glacier. The water lubricates the glacier so that it can move.
Compare and contrast lateral moraines and eskers.
They are similar because they are both linear deposits. They are different because one is a glacial deposit and the other is a deposit from a river running through a glacier. Also, lateral moraine is straight, but the esker meanders.
drumlin
another pile of sediment under a glacier shaped like a drumstick
Describe how a cirque forms.
as the glacier flows downhill, it abrades the side of the mountain forming a bowl shape as it flows down
cirque
bowl at the top of the valley
plucking
cold water pressurized by glacier goes into the cracks of a rock, freezes, and the glacier flows over the rock and picks it up/ moves it
esker
deposit from a river that was flowing through the glacier
plastic flow
flowy solid formed when ice is under a lot of pressure
hanging valley
formed from a smaller glacier meeting a larger glacier
How do hanging valleys form?
formed when a smaller glacier meets a larger glacier
How did the great lakes form?
from extreme abrasion (from the glacier) which scoured out a divot
How did the finger lakes form?
from extreme abrasion which created giant grooves that filled up with water
Describe the processes that glaciers use to weather and erode.
frost heaving: Water gets into the cracks of rocks, freezes, expands, and cracks the rock. The rock is broken off of the mountain and the glacier pulls it away. When the rocks tear across the bottom of the valley because they are being tugged by the glacier, this causes abrasion: the rock rubs against/ destroys the bottom of the valley. plucking: Cold water pressurizes by glacier goes into the cracks of rock, freezes, and glacier flows over the rock and picks it up/ moves it. (pressure uphill, less pressure downhill)
glacial erratic
huge boulders deposited randomly by the glacier that tend to have no relation to the local rocks
continental glacier
huge glaciers formed at the poles that flow towards the equator (flatten topography)
glacier
ice moving under its own weight on land
firn
iceballs
angular
jagged-edged rocks
kettle lake
lake formed in the indentation from a leftover piece of ice (water flows around big ice, depositing sediment on either side creating mountains with lakes at the bottom)
tarn
lake in a cirque
lateral moraine
pile glacier left on its sides
ground moraine
pile glacier left underneath
medial moraine
pile of rocks between 2 glaciers
end moraine
pile of rocks in front of glaciers
arete
pile of rocks left behind by 2 parallel glaciers
outwash
river deposit from meltwater
abrasion
rocks tearing/rubbing against the bottom of the valley
moraine
rocks that were pushed by the glacier
rounded
rocks with smooth edges
alpine glaciers
smaller glaciers formed at the top of mountains that flow downhill (intensify topography)
basal slipping
the process of the glacier moving over its bed because of the meltwater lubricating the glacier
terminal moraine
very last end moraine
frost heaving
water gets into the cracks in rocks, freezes, expands, and cracks the rock/breaks them off the mountain: the rock gets attached to the glacier and the glacier pulls it away
polished
when a glacier smooths out the topography of a certain area
How do medial moraines form?
when two glaciers meet