GLACIATION
About 15 million square kilometres of the earth’s surface are currently covered with glaciers
Continental ice sheets
Two Types of Glaciers Continental: found at high LATITUDES ex. Greenland, Antarctica Alpine: found at high ALTITUDES ex. Western Cordillera
How GLACIERS Form Two conditions need to be present: . Prolonged cold . Accumulation of snow Over time, the overlying layers of snow compress the lower layers until it becomes ice.
How Do Glaciers MOVE? Glaciers move like a very thick liquid Depending on the climate, a glacier can do one of three things: Advance Stay Stationary Retreat Mass Balance: the rate of accumulation is balanced by the rate of ablation (melting)
How Do Glaciers Alter the Landscape? Glaciers leave evidence on the landscape in the form of erosional features: Striations U-shaped Valleys Spillways Misfit Streams
Depositional Features 1. Ice Deposits Till Moraines Drumlins Erratics 2. Meltwater Deposits Eskers Outwash plains
A Moraine
Oak Ridges Moraine
Spillway with a Mistfit stream
V- Shaped Valley
U-Shaped Valley
How ice alters the landscape 1. scraps or scours - like sandpaper - rocks are embedded into the bottom of the ice sheet and erode the bedrock as it flows conveyor belt - embedded rocks are carried in the ice and deposited in the front as the glacier flows 3. plucking - ice freezes onto the rock and pulls or plucks it away as it flows 4. bulldozer - material is pushed along in front
The End!