Glaciation EQ1

  • Created by: ellaweez
  • Created on: 08-04-18 14:04
What is the main long-term cause of glacial cycles?
Changes in the Earth's orbit around the sun
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What 3 characteristics does the Milankovitch theory attribute?
Eccentricity, axial tilt and wobble
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What are the short-term causes of glacial cycles?
Fluctuations in energy emitted by the sun (e.g. more sunspots = warmer climate) AND volcanic activity - eruptions can reduce the amount of solar energy reaching the Earth
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Define: cryosphere
Parts of the Earth's crust subject to below 0 temperatures for part of the year
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What are the characteristics of a warm-based glacier?
Occur in high altitudes / Found outside of polar regions / Generate lots of meltwater in summer which allows them to slide over bedrock
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What are the characteristics of a cold-based glacier?
Occur in high latitudes (e.g. Antarctica/Greenland) / No basal sliding as temperatures are well below freezing
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Define: periglacial landscapes
Areas found at the edge of polar environments and are underlain by permafrost
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Define: permafrost
Soil/rock that remains frozen for at least 2 years
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What are the 3 types of permafrost?
Continuous, discontinuous and sporadic
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What are the characteristics of periglacial environments?
Intense frosts during winter / Low precipitation / Cycles of freezing and thawing / Daily temp below 0 for at least 9 months
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Define: the active layer
The area above the permafrost which thaws during summer and freezes during winter
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What factors will influence the distribution of permafrost?
Climate - depth, extent / Slope angle - solar radiation, melting / Rock and soil type - degree, depth / Vegetation cover - insulation
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Name some periglacial processes
Freeze-thaw weathering / Nivation / Solifluction / Wind action / Meltwater action
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Define: freeze-thaw weathering
The shattering of rock as a result of water in its joints and pores freezing and expanding
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Define: nivation
When a combination of processes weakens and erodes the ground
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Define: solifluction
Downslope movement of the saturated active layer under the influence of gravity
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Define: wind action
When a lack of vegetation cover allows strong wind to pick up and transport sediment which is deposited
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Name some periglacial landforms
Ice-wedge polygons / Loess / Scree / Patterned ground / Pingo
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Define: ice-wedge polygon
When the active layer thaws, ice-wedges can form as water flows down into cracks and freezes
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Define: loess
When sediment is deposited by the wind in glacial conditions
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Define: scree
An accumulation of weathered rock fragments at the base of a slope/cliff
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Define: patterned ground
Stone circles/polygons/stripes found in soils subjected to intense frost action
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Define: pingo
An isolated hill formed by the movement/freezing of water
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Other cards in this set

Card 2

Front

What 3 characteristics does the Milankovitch theory attribute?

Back

Eccentricity, axial tilt and wobble

Card 3

Front

What are the short-term causes of glacial cycles?

Back

Preview of the front of card 3

Card 4

Front

Define: cryosphere

Back

Preview of the front of card 4

Card 5

Front

What are the characteristics of a warm-based glacier?

Back

Preview of the front of card 5
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