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Published byLorin Simon Modified over 9 years ago
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More Erosion Or... you’re really wearing me down.
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Wind Erosion Wind can be a significant agent of erosion in beach areas, deserts and semi-arid regions such as the U.S. Southwest. Wind can be a significant agent of erosion in beach areas, deserts and semi-arid regions such as the U.S. Southwest.
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In both beach and desert areas, wind can move sand into large dunes. In both beach and desert areas, wind can move sand into large dunes.
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Barchan Dune
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Wind lifting loose material (deflation) from desert floors creates desert pavement Wind lifting loose material (deflation) from desert floors creates desert pavement Desert pavement is a surface of coarse pebbles and cobbles. Desert pavement is a surface of coarse pebbles and cobbles.
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Road Runner
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Wind blown sand (sandblasting) can scour rock formations into interesting shapes. Wind blown sand (sandblasting) can scour rock formations into interesting shapes.
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Wind can blow away precious topsoil from farm land. As shown in this picture from the Dust Bowl ca. 1932. Wind can blow away precious topsoil from farm land. As shown in this picture from the Dust Bowl ca. 1932.
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Glaciers Two kinds Two kinds Ice Sheets or Continental Glaciers Ice Sheets or Continental Glaciers Valley or Alpine Glaciers Valley or Alpine Glaciers A continental glacier called the Laurentide Ice Sheet covered most of NYS during the last ice age. A continental glacier called the Laurentide Ice Sheet covered most of NYS during the last ice age.
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Alpine or Valley Glaciers cover a much smaller area. Sometimes only a valley. Alpine or Valley Glaciers cover a much smaller area. Sometimes only a valley.
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Glaciers push sediments out front (end or terminal moraine) and drag it along the sides (lateral moraine) Glaciers push sediments out front (end or terminal moraine) and drag it along the sides (lateral moraine)
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A glacier’s movement downhill is due to it’s own weight and gravity. A glacier’s movement downhill is due to it’s own weight and gravity. If more snow and ice accumulates than melts, a glacier will advance. If more snow and ice accumulates than melts, a glacier will advance. A glacier’s movement is similar to a stream in that its middle moves fastest and the sides and bottom more slowly. A glacier’s movement is similar to a stream in that its middle moves fastest and the sides and bottom more slowly.
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A glacier’s weight and sediments beneath it carve deep parallel grooves and scratches into bedrock called striations. A glacier’s weight and sediments beneath it carve deep parallel grooves and scratches into bedrock called striations. The direction of these striations shows the direction of former glacial movement. The direction of these striations shows the direction of former glacial movement. Evidence of Glaciation Striations
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Ayers Rock, Australia
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The wide, thick ice of a glacier erodes the valley walls as much as the rock beneath it thereby forming a U-shaped valley. The wide, thick ice of a glacier erodes the valley walls as much as the rock beneath it thereby forming a U-shaped valley. U-Shaped Valleys
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Glaciers can move sediments for miles. When they melt they often leave boulders that are a different type of rock from the bedrock beneath them. These are called eratics. Glaciers can move sediments for miles. When they melt they often leave boulders that are a different type of rock from the bedrock beneath them. These are called eratics. Eratics
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Unsorted Sediments Glaciers mix sediments of all sizes and shapes. The sediment deposits are unsorted. Glaciers mix sediments of all sizes and shapes. The sediment deposits are unsorted.
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The Finger Lakes
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The Finger Lakes consist of 11 long, narrow, roughly parallel lakes, oriented north-south as fingers of a pair of outstretched hands. The southern ends have high walls, cut by steep gorges. These lakes all formed over the last two million years by glacial carving of old stream valleys. The deepest of which is Seneca at 618 feet. The Finger Lakes consist of 11 long, narrow, roughly parallel lakes, oriented north-south as fingers of a pair of outstretched hands. The southern ends have high walls, cut by steep gorges. These lakes all formed over the last two million years by glacial carving of old stream valleys. The deepest of which is Seneca at 618 feet.
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Glacial Features - Cirques
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Glacial Features - Horn
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Glacial Features - Drumlin
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Glacial Deposit - Esker
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Glacial Feature – Kettle Lake
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