Glaciation

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What is an ice age?
Long period of time where global temperature is very cold and large areas were covered with sheets of ice
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What is an inter glacial period?
A short term period of warmer temperatures within an ice age. (current one is called the Pliestocene ice age)
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What are ice sheets?
Large areas of solid ice which completely cover continents. E.g. Antarctica
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What are valley glaciers?
Tongues of ice that 'flow' down valleys. Short valley glaciers are called corries or cirques
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How do glaciers begin?
Snow compaction on sheltered valley turns into Neve and eventually into ice. Eventually due to accumulation, they begin to flow downhill.
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What is the glacial budget?
Balance between accumulation (snow & avalanches) and ablation (melting) of a glacier.
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What happens when accumulation and ablation are not balanced?
More accumulation- glacier will advance. More ablation- glacier will retreat
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Name the erosional processes that operate in glacial environments
Glacial erosion, abrasion, plucking
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What is glacial erosion?
Angular weathered rock fragments under ice act like sand paper and grind away valley floor and sides. Leaving smooth surface
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What is abrasion?
Erosion involving wearing away of glaciers and the shoreline (coastal zones)
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What is plucking?
Erosion where individual rocks are plucked from valley floor as water freezes the, to the glacier.
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How does a glacier move?
Melting at bottom of ice sheet produces meltwater which lubricates the ice, allowing it to slide.
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How do glaciers move in a cirque?
Ice moves in rotational slip (circular direction). In winter, much less melting but weight of glacier causes slow movement by internal deformation.
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What is moraine?
General term to describe debris carried by a glacier. When angular rocks form thick layer, it's known as till or boulder clay.
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What is ground moraine?
Material dragged underneath glacier which is left behind when ice melts.
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What is lateral moraine?
Forms at edge of glaciers. Mostly scree fallen of valley sides.
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What is medial moraine?
When tributary glacier joins main glacier lateral moraines join to produce one single line of sediment in the center of the main glacier.
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What is terminal moraine?
Big amounts of material pile up at snout of glacier. Meltwater often erodes away moraine features, leaving only fragments.
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What is the G.I.S?
Geologiacl information systems- digital data in form of tables or maps which helps people understand patterns. Eg. flooding or shopping patterns
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What are the causes of avalanches?
Heavy snowfall; Steep slopes; Deforestation; Temperature rise; Heavy rainfall; Human facors (eg. off piste skiing)
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What is an avalanche?
Rapid downhill movement of mass of snow, ice and rocks usually in mountainous environments.
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What are the two types of avalanches?
Loose snow avalanches (powdery avalanche) & Slab avalanches (large-scale when slab of ice and snow breaks away from main ice pack.
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State a case study of a recent avalanche
Kashmir Feb 2008- heavy snowfall & killed 30. Europe 2006-irregular weather patterns, 49 killed off piste.
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Other cards in this set

Card 2

Front

A short term period of warmer temperatures within an ice age. (current one is called the Pliestocene ice age)

Back

What is an inter glacial period?

Card 3

Front

Large areas of solid ice which completely cover continents. E.g. Antarctica

Back

Preview of the back of card 3

Card 4

Front

Tongues of ice that 'flow' down valleys. Short valley glaciers are called corries or cirques

Back

Preview of the back of card 4

Card 5

Front

Snow compaction on sheltered valley turns into Neve and eventually into ice. Eventually due to accumulation, they begin to flow downhill.

Back

Preview of the back of card 5
View more cards

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