GLACIATION About 15 million square kilometres of the earth’s surface are currently covered with...

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GLACIATION GLACIATION

Transcript of GLACIATION About 15 million square kilometres of the earth’s surface are currently covered with...

Page 1: GLACIATION About 15 million square kilometres of the earth’s surface are currently covered with glaciers.

GLACIATIONGLACIATION

Page 2: GLACIATION About 15 million square kilometres of the earth’s surface are currently covered with glaciers.

About 15 million square kilometres of the earth’s surface are currently covered with glaciers

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Continental ice sheets

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Two Types of GlaciersTwo Types of Glaciers

• Continental:Continental: found at high found at high LATITUDES ex. Greenland, LATITUDES ex. Greenland, AntarcticaAntarctica

• Alpine:Alpine: found at high ALTITUDES found at high ALTITUDES ex. Western Cordilleraex. Western Cordillera

Page 5: GLACIATION About 15 million square kilometres of the earth’s surface are currently covered with glaciers.

How GLACIERS FormHow GLACIERS Form

Two conditions need to be present:1 . Prolonged cold2 . Accumulation of snow

• Over time, the overlying layers of snowsnow compress thelower layers until it becomes ice.ice.

Page 6: GLACIATION About 15 million square kilometres of the earth’s surface are currently covered with glaciers.

How Do Glaciers MOVE?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)

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How Do Glaciers Alter How Do Glaciers Alter the Landscape?the Landscape?

• Glaciers leave evidence on the landscape in the form of erosional features:

–Striations–U-shaped Valleys

–Spillways–Misfit Streams

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Depositional FeaturesDepositional Features

1. Ice 1. Ice DepositsDeposits– Till – Moraines– Drumlins– Erratics

2. Meltwater 2. Meltwater DepositsDeposits– Eskers– Outwash plains

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A Moraine

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Oak Ridges Moraine

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Spillway with a Mistfit stream

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V- Shaped Valley

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U-Shaped Valley

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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

2. 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

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The End!