Masses of Ice that: 1)Are at least 100 m thick 2)Originate on land 3)Move How Glaciers Form

1)Ice sheets/continental glaciers 2)Ice shelves 3)Alpine/mountain glaciers

Largest glaciers on Earth Greenland and Antarctica Covered nearly all of Canada yrs ago during the last Ice Age 30% of Earth was covered by glaciers during the last Ice Age

Ice sheets that are attached to land but float on water too They can be over 1 km thick and 100’s of km from land

Smaller than Ice Sheets/Shelves Only at high elevations Create valleys and unique mountain features Alpine Glaciers in North America have been melting very quickly over the last years

Today Glaciers only cover ~2% of Canada’s land They have helped shape nearly all of Canada’s landform regions Very important for the water cycl e

When Glaciers move forward they are said to advance When they melt they are said to be retreating

Crevasses can be hundreds of metres deep

1)Plucking Melting water goes into cracks in rock  freezes and expands  pry's rocks loose Sediment as fine as flour to boulders the size of houses become part of the glacier 2) Abrasion Rocks plucked by the glacier grind away the rock surface underneath the glacier

The large volume of sediment that glaciers transport as they advance over land are deposited when the ice eventually melts In S. Ontario the bedrock is rarely exposed because the glacier melted and deposited (left behind) ’s of metres of sediment Sediment from a glacier is called drift – clay, sand, gravel, rocks, boulders

1) Drumlin