Snow line – where snow remains year round. Formation of Glacial Ice from Snow.
Post on 21-Dec-2015
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Snow line – where snow remains year round
Formation of Glacial Ice from Snow
Forming Glacial Ice
Initial Form
2 weeks
7 weeks
8 weeks
Snow Firn Glacial Ice
Glacier movement
• When glacier reaches critical mass (> 20m thick), flow occurs
Types of Glaciers
slip
Plasticdeformation
Ice Deformation with Slip
What happens as ice melts
• Ice melt flows down to bedrock through crevasses and moulins (large tunnels)
• Water between bedrock and ice sheet acts as lubricant
• Allows ice sheet to move faster toward the coastline
• Ice movement-rate increases from~30 cm per day in winter to ~40 cm per day in the summer
Terminus
Advance & Retreat: Moraines
Alpine Moraines and Till
Moraine Types
Anatomy of a Glacier
Piedmont glacier
Types of Glaciers – Piedmont & Tidewater Piedmont: Originally confined alpine, spread at foot of mountains
Calving
Different kinds of glaciers
Ice extent Last Glacial Maximum (21,000 yr BP)
Retreat of North American (Laurentide) ice sheet
Different kinds of glaciers
Ice cap and continental (ice sheet)
Sentinal Range, Antarctica
Ice cap (Vatnakjokull in Iceland)feeds “outlet glaciers”
Greenland Ice Sheet
Greenland
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