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Glaciers!
Mr. Drake Phy. Sci.
55
Geology
10th Grade
03/29/2007

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Cards

Term
What is a valley glacier?
Definition
Smaller glaciers found in the mountains on overy continent except Australia. They carve U-shaped valleys into mountain ranges.
Term
What is an iceberg?
Definition
A giant piece of ice floating in the water that has broken off from an ice sheet. 90% of an icberg is underwater.
Term
What is a continental glacier?
Definition
An enormously large and thick sheet of ice found only in Antarctica and Greenland that moves slowly outward from the center. Roughly circular or oval in shape.
Term
What is the snow line?
Definition
The lowest level that permanent snow reaches in the summer on a mountain.
Term
Where can glaciers exist/begin?
Definition
Glaciers can only exist in areas where there is more snowfall than melted snow every year.
Term
What is firn?
Definition
A rough, granular ice material found in a glacier.
Term
What is another name for a continetal glacier?
Definition
An ice sheet.
Term
What is a nunatak?
Definition
The exposed summit of a ridge, mountain, or peak not covered with ice or snow within a glacier.
Term
What is an ice cap?
Definition
A smaller ice sheet.
Term
What are crevasses?
Definition
Great cracks upto 40 m deep in a glacier. Ice is brittle up to this depth.
Term
What is an ice front?
Definition
Point where ice melts as fast as it moves.
Term
What is calving?
Definition
The process of huge chunks of ice breaking off an ice sheet to form icebergs.
Term
What are moraines?
Definition
Deposits of materials carried by a glacier.
Term
What is a ground moraine?
Definition
Material carried in the bottom of a glacier before it is deposited.
Term
What is a ground moraine?
Definition
Material carried in the bottom of a glacier before it is deposited.
Term
What are lateral moraines?
Definition
Materials glaciers pick up from valley walls.
Term
What are medial moraines?
Definition
Long winding lines in the middle of a glacier formed when two glaciers combine along with their lateral moraines.
Term
What is an end moraine?
Definition
Deposits formed when glicer reaches ice front and maltes, releasing materials.
Term
What is rock flour?
Definition
A mixture of fine sand and silt formed by the crushing of rock under a glacier.
Term
What is glacial milk?
Definition
Water coming out of a glacier that is mixed with glacial flour.
Term
How do glaciers erode rock?
Definition
Largely by using rocks as cutting tools.
Term
What are striations?
Definition
Long parallel scratches left on bedrock from pebbles and gravel. Indicate direction of glacier.
Term
What is a cirque?
Definition
A semicircular basin formed at the head of a glacial valley. Glaciers start here.
Term
What is an arete?
Definition
A sharp ridge in between two cirques.
Term
What is a horn? Give an example.
Definition
A pyramid-shaped peak formed when three or more ciques cut into the same peak. Ex. The Matterhorn in Switzerland.
Term
What is a glacial trough?
Definition
A glacial valley that is roughly U-shaped.
Term
What is a hanging trough?
Definition
A tributary glacial valley.
Term
What is a hanging trough waterfall?
Definition
A waterfall formed when rivers begin in hanging trough valleys.
Term
How does the erosion from continental glaciers differ from the erosion from vally glaciers?
Definition
Continental glaciers round off and polish mountain peaks and ridges. Valley glaciers sharpen peaks by grinding away at their sides
Term
What is drift?
Definition
Any deposit of glacial origin.
Term
What are the two kinds of drift?
Definition
Till and outwash.
Term
What is till?
Definition
UNSORTED and unstratifed rock material deposited directly by glacier.
Term
What is outwash?
Definition
Deposits made by glacial streams. Due to this, out wash is SORTED.
Term
What is a terminal moraine?
Definition
The deposit from the glaciers farthest advance.
Term
What causes an end moraine to grow larger?
Definition
If the ice does not advance for a long time. B/c the ice is still all moving forward along with the materials in it.
Term
What are drumlins?
Definition
Long, smooth, canoe-shaped hills made of till. Usually found in swarms. Formed when a glacier ran over a preexisting moraine.
Term
What are outwash plains?
Definition
Gently sloping sorted deposits of out was that form from glacial streams.
Term
What are eskers?
Definition
Long winding ridges that are deposits from subglacial streams.
Term
What are kames?
Definition
Small, cone-shaped hills of stratified sand and gravel. How are they formed?
Term
What are kettles?
Definition
Circular hollows found on terminal moraines and out wash plains. Formed when large blocks of ice are buried in terminal moraine and ice melts.
Term
What are glacial deltas?
Definition
Formed when glacial streams empty into lakes.
Term
What are two other names for a valley glacier?
Definition
Mountain glacier, alpine glacier.
Term
What type of glacial period do we live in?
Definition
An interglacial period.
Term
How many times have glaciers gone over A2 in last 2 mil. years?
Definition
4
Term
How do all glaciers move forward?
Definition
By internal deformation.
Term
How do valley glaciers move in warm climates?
Definition
By basal sliding (and internal deformation)
Term
What is basal sliding?
Definition
The entire glacier sliding down the slope lubricated by meltwater.
Term
What is internal deformation?
Definition
Occurs when ice and ice crystals move over and around each other.
Term
Do glaciers have a lot of force?
Definition
Yes, F=m*a and they have A LOT of mass.
Term
Glaciers are a(n) __________ and a __________ force.
Definition
erosional, depostional.
Term
Why might a glacial ice age start?
Definition
If all 3 of these happen at once:
1. Times in our orbit when we are a little farther away
2. Earth changes its axis every so often
3. Fo some reason we get less energy from the sun
Term
How much does the planet have to go down for an ice age to start?
Definition
Only 4-5 degrees F
Term
What is the rule about what latitude and altitude glaciers must form at?
Definition
The greater the latitude, the less the altitude has to be and vice versa.
Term
What are the different sections of a glacier?
Definition
The top 30-40 m are brittle (crevasses can form). The rest is called plastic. It is so dense that it is extremely hard(about a 5 on Mohs scale).
Term
Glaciers can calve underwater. T/F?
Definition
True!
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