8 - Ocean Circulation and Cryosphere Flashcards
Glaciers
accumulations of ice and snow that form on land and slowly move downhill due to gravity
Why are glaciers blue?
Due to compressed ice which absorbs all colours of light except blue (shortest wavelength) which it reflects.
glacial erosional features?
tarn, arete, horn (pyramidal peak), hanging valley, glacial step
glacial depositional features?
esker, kames, erratics, moraines, outwash fan
How does snow form?
Occurs when ice crystals form in clouds and clump together to create snowflakes
Avalanches
rapid flow of snow down slope. Composed of snow and air but can capture ice, rocks and trees
How does a glacier move?
Internal deformation, basal sliding and deforming bed
Internal deformation
occurs in cold glaciers (frozen sediment) where gravity and ice pressure causes crystals to slide over each other in a series of parallel planes. Results in crevasses at the surface
Basal sliding
when friction between the glacier and earth surface causes melting. This acts as a lubricant across which the glacier can move
Deforming bed
when unfrozen sediment beneath the glacier is deformed, causing glacial movement
Calving
way in which glaciers lose mass by chunks breaking off, commonly into proglacial lakes.
When was the last glacial maximum?
20,000 years ago (25% of land area covered)
Which ice age affected Utrecht?
Second to last ice age - Saale Ice Age (150,000 years ago)
Why is it difficult to predict changes in Antarctic ice loss?
Due to its large size and constant change - especially in large calving events
Effects of climate change on ocean circulation?
AMOC likely to collapse due to increasing cold water from the Arctic. This would make Europe colder
