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GlaciersGlaciersGlaciers are made up of fallen snow that, Glaciers are made up of fallen snow that, over many years, compresses into large, over many years, compresses into large,

thickened ice masses. Glaciers form when thickened ice masses. Glaciers form when snow remains in one location long enough snow remains in one location long enough to transform into ice. What makes glaciers to transform into ice. What makes glaciers

unique is their ability to move. Due to unique is their ability to move. Due to sheer mass, glaciers flow like very slow sheer mass, glaciers flow like very slow

rivers. Some glaciers are as small as rivers. Some glaciers are as small as football fields, while others grow to be football fields, while others grow to be

over a hundred kilometers long.over a hundred kilometers long.

Quick FactsQuick Facts

�� Presently, 10% of land area is covered with glaciers.Presently, 10% of land area is covered with glaciers.

�� Glaciers store about 75% of the world's freshwater.Glaciers store about 75% of the world's freshwater.

�� Glacierized areas cover over 15,000,000 square Glacierized areas cover over 15,000,000 square kilometers.kilometers.

�� Antarctic ice is over 4,200 meters thick in some areas.Antarctic ice is over 4,200 meters thick in some areas.

�� During the last Ice Age, glaciers covered 32% of the During the last Ice Age, glaciers covered 32% of the total land area.total land area.

�� If all land ice melted, sea level would rise If all land ice melted, sea level would rise approximately 70 meters worldwide.approximately 70 meters worldwide.

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Alpine GlaciersAlpine GlaciersAlpine glaciers form in high mountain valleys above the Alpine glaciers form in high mountain valleys above the

snowline.snowline.

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Continental GlaciersContinental Glaciers

�� Continental glaciers are large ice Continental glaciers are large ice sheets covering major portions of sheets covering major portions of entire continental land areasentire continental land areas

�� Today they are found covering large Today they are found covering large portions of Greenland and Antarctica.portions of Greenland and Antarctica.

�� The erosional and depositional The erosional and depositional effects are found throughout most effects are found throughout most areas in the Northern Hemisphere.areas in the Northern Hemisphere.

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Glaciers Erode In Three WaysGlaciers Erode In Three Ways

1)1) Glacial ice pushes loose material Glacial ice pushes loose material along the sides and in front of it in along the sides and in front of it in a kind of bulldozing action. This a kind of bulldozing action. This material is often incorporated into material is often incorporated into the glacier as the ice flows over it.the glacier as the ice flows over it.

Glaciers Erode In Three WaysGlaciers Erode In Three Ways

2)2) The material embedded in the ice The material embedded in the ice gouges out new material from a gouges out new material from a new surface. new surface.

Rock surfaces that have been Rock surfaces that have been glaciated can either have smooth glaciated can either have smooth surfaces called glacial polish or surfaces called glacial polish or scratches and gouges called glacial scratches and gouges called glacial striations.striations.

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Glaciers Erode In Three WaysGlaciers Erode In Three Ways

3)3) Ice freezes to underlying rock Ice freezes to underlying rock surfaces and as the ice flows surfaces and as the ice flows forward, it pulls or plucks out forward, it pulls or plucks out fragments.fragments.

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Arête:Arête: a steepa steep--sided, sharpsided, sharp--edged bedrock edged bedrock ridge formed by two glaciers eroding away ridge formed by two glaciers eroding away

on opposite sides of the ridge.on opposite sides of the ridge.

CirqueCirque :: a semicircular or amphitheatera semicircular or amphitheater--shaped shaped bedrock feature created as glaciers scour back bedrock feature created as glaciers scour back into the mountain. This is where the snow and into the mountain. This is where the snow and

ice forming the glacier first accumulates; it is the ice forming the glacier first accumulates; it is the "headwaters" of a glacier."headwaters" of a glacier.

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MorainesMoraines

•• Lateral Lateral –– lower energy at sides of glaciers lower energy at sides of glaciers causes deposit of glacial debris.causes deposit of glacial debris.

•• Medial Medial –– lateral moraine of two adjacent lateral moraine of two adjacent glaciers join.glaciers join.

•• Terminal Terminal –– lower energy at snout of lower energy at snout of glaciers causes deposit of glacial debrisglaciers causes deposit of glacial debris

Lateral MoraineLateral Moraine

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Medial MoraineMedial Moraine

Terminal Moraine

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FiordFiord

�� A drowned U A drowned U ––shaped valley filled shaped valley filled with sea water.with sea water.

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Western Brook PondWestern Brook Pond