glaciation Flashcards

1
Q

what is a glacier?

A

a mass of ice formed by the accumulation and compaction of snow

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2
Q

how are glaciers created?

A

hundreds of meters of snow accumulates, and the bottom of the pile compresses into ice

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3
Q

what does it mean when a glacier advances?

A

rate of accumulation > rate of melt

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4
Q

what does it mean when a glacier retreats?

A

rate of accumulation < rate of melt

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5
Q

what does it mean when a glacier is stationary?

A

rate of accumulation = rate of melt

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6
Q

what is a valley glacier also known as?

A

alpine glaciers

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7
Q

valley glaciers move from ______ to _______ elevations due to gravity

A

high / low

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8
Q

what happens if the valley opens onto flat land?

A

the glacier spreads out

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9
Q

how and why do the glaciers move?

A

outwards under their own weight in all directions

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10
Q

how do glaciers change the landscape?

A

they scrape the land, loosening rock and soil which becomes part of the glacier.
the glaciers scrape so hard that they leave marks on the earth

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11
Q

what is a drumlin?

A

an oval shaped hill made of glacial deposits

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12
Q

what is an erratic?

A

a large boulder that was picked up by a glacier and deposited far from its original surroundings

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13
Q

what is an ice cave?

A

an opening in the front of a glacier that is formed when glacial ice melts

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14
Q

what is an ice floe?

A

a large sheet of free floating ice

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15
Q

what is an ice shelf?

A

a large sheet of ice attached to a glacier or to land but extends into the ocean

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16
Q

what is a lateral moraine?

A

a mounded glacial deposit at the bottom of a valley

17
Q

what is a striation?

A

grooves in rock made by passing glaciers

18
Q

what is a terminal moraine?

A

a glacial hill deposit that marks the end of a glacier’s forward movement