Cold Environments Flashcards
Why do glacial sand interglacial happen
Milankovitch cycles Volcanic eruptions Sunspot activity variation Changes in atmospheric carbon dioxide Continental drift Variation in ocean currents
Milankovitch cycle
The 95 000 year stretch
The 42 000 year tilt
The 21 000 year wobble
Development of a glacier
Snow lands as a snowflake
New snow lands and air is compressed out of forming granular snow
More air compressed out forming firn
Years of compression form glacier ice
How glaciers occur
Ice/snow must remain in the ground for a year
Snow line
Zone of accumulation
Zone of ablation
Equilibrium
Above the snow line
Below the snow line
Cold base glacier (polar)
Temperature is V. Cold
Gentle gradient
Due to extreme cold ice does not melt (even under pressure)
Moves by internal flow
Warm based glacier (alpine)
Varying temperature
Steep gradient
Summer melting + pressure melting point
Basal slippage
Glacial movement
Creep
Compressing & extending
Surge
Erosion processes
Abrasion
Plucking