What is the main long-term cause of glacial cycles?
Changes in the Earth's orbit around the sun
1 of 23
What 3 characteristics does the Milankovitch theory attribute?
Eccentricity, axial tilt and wobble
2 of 23
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
3 of 23
Define: cryosphere
Parts of the Earth's crust subject to below 0 temperatures for part of the year
4 of 23
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
5 of 23
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
6 of 23
Define: periglacial landscapes
Areas found at the edge of polar environments and are underlain by permafrost
7 of 23
Define: permafrost
Soil/rock that remains frozen for at least 2 years
8 of 23
What are the 3 types of permafrost?
Continuous, discontinuous and sporadic
9 of 23
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
10 of 23
Define: the active layer
The area above the permafrost which thaws during summer and freezes during winter
11 of 23
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
Comments
No comments have yet been made