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10 Cards in this Set
- Front
- Back
Louis Agassiz
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-19th century Swiss geologist
-Suggested that eupope and north america were covered by thick ice sheets in the recent geologic past. |
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Evidence for past continental scale ice sheets
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Erratic boulders, Ground moraine found in northern parts of US and Europe, Glacial straiations on rocks, layers of till.
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Erratic boulders
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-large boulders transported by glacial ice.
-can be traced back to their source rock bodies, marking flow direction of ice sheets. |
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Milutin Milankovitch
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-1930's
-calculated the amount of sunlight each latitude received in every phase of earth's orbital variations. -Pacemaker of the Ice ages |
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Milankovitch Theory
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Ice ages occur when orbital variations cause the northern hemisphere to receive less sunshine in the summer. Predicted that ice ages would peak every 100,000 and 41000 years.
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Axial tilt affect on solar radiation
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When the tilt is decreased, polar regions receive less sunlight; when it is increased, polar regions receive more sunlight.
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Positive feedback factors
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-A changing albedo- increased snow on land
-Less evaporation-sea is less salty -Biological processes that change CO2 concentration. |
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Pleistocene interglacials typically lasted how long?
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10,000 years
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The precent interglacial began how many years ago?
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13,000
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Little Ice Age
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-1300'2-mid 1800's
-Montain glaciers advanced significantly. |