Presentation on theme: "Erosion The movement of sediments by wind, water, ice, or gravity."— Presentation transcript:
Erosion The movement of sediments by wind, water, ice, or gravity.
By Gravity Erosion by gravity is referred to as Mass Movement. There are 4 types of mass movement Landslides Mudflows Creep Slump
Landslides Loose rock and soil slide quickly down hill. Creates a snowball effect Occurs on a steep slope Happens very fast
Mudflows Occurs when mud slides down hill. Usually occurs in dry areas after a lot of rain. Can occur during a volcanic eruption (snow melt) Occurs on a gentle or steep slope Happens very fast.
Creep Soil gradually slips downhill over several years. Created by continuous freezing and thawing Usually occurs on gentle slopes Happens very slowly.
Slump When a large section of land breaks away from a hill and drops down in one large chunk. Usually occurs when bottom of hill is saturated (coastlines) Occurs along steep slope. Very quick.
By Ice A glacier is any large mass of ice that moves slowly over land. There are 2 types of glaciers: Valley glaciers Continental Glaciers
Valley Glaciers A long narrow glacier that forms when snow and ice build up in a mountain valley.
Continental Glaciers A glacier that covers much of a continent or large island. There are only 2 continental glaciers left: Antarctica and Greenland.
Glacial Erosion As valley glaciers move over the earth they pick up sediments (Plucking) and scrape against other rocks (Abrasion) to carve out features in the landcapes. As valley glaciers move over the earth they pick up sediments (Plucking) and scrape against other rocks (Abrasion) to carve out features in the landcapes.
Arete A sharp ridge separating 2 cirques.
Horn A sharp peak
Cirque Bowl-shaped hollow
U-Shaped Valley A valley scraped out by a glacier. In the shape of a half-pipe or U.
Glacial Deposition When a glacier melts, it deposits the sediment it eroded (till)—b., creating various landforms.
Moraine (a) A hill or mound of till left behind by a glacier.
Erratic (c) Large boulder dropped off as a glacier retreats..
Drumlin Long mound (moraine) that has been smoothed in the direction of a glacier retreat.
Kettle A lake that forms because a chunk of ice breaks off a glacier and melts.
Ice Ages A Time in Earth’s History when most of the Earth was covered in Glaciers. Global temperatures were only 3 degrees colder than they are today.
By Wind Weakest agent of erosion Mainly caused by Deflation.
Process by which wind removes surface materials. Stronger wind moves larger particles. Abrasion polishes rock but creates little erosion.
Wind Deposition Two types of landforms created by wind deposition. Sand Dunes Move over time Build up on an obstacle (rock/boulder) Loess deposits Fine sediments build up in layers Helps to form fertile soil.