Ice Ages - Ice Ages Pleistocene 3 M.y. Permian 250-220 M.y....

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Ice Ages Pleistocene 3 M.y. Permian 250-220 M.y. Ordovician 450 M.y. Precambrian 900-650 M.y. (Snowball Earth) 2300 M.y .
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Take-Away Points 1. The recent period of ice advances since 2.5 million years ago is called the Pleistocene 2. The best record of Pleistocene ice advances is on the sea floor 3. There were probably 20+ advances of the ice, of which only the last few are preserved on land. 4. Over most of the earth’s history, the earth has been mostly ice free 5. Tiny changes in earth’s orbit and axis tilt play a role in ice advances by varying the amount of sunlight we receive 6. The carbonate-silicate cycle governs the balance of carbon dioxide in the atmosphere and in rocks and creates “icehouse” and “greenhouse” periods 7. We still have no final answer why ice ages occur
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Time (1000 Years) North America Alps Northern Europe Poland-Russia 0-18 Interglacial 18-67 Wisconsin Wurm Vistula Varsovian 67-128 Sangamon Uznach Eem Masovian 128-180 Illinoisan Riss Warthe/Saale Cracovian 180-230 Yarmouth Hoetting Holstein Sandomirian 230-300 Kansan Mindel Elster Jaroslavian 300-330 Aftonian Cromer Likhvin 330-470 "Nebraskan " Gunz Menapian 470-540 Waalian 540-550 Donau II Weybourne 550-585 Tiglian 585-600 Donau I 600-2000 About 20 Glacial Advances 2000 (2 M.Y.) Beginning of Pleistocene 4000 (4 M.Y.) Dwarf forests still in Antarctica 15 M.Y. First Glaciation in Antarctica
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This note was uploaded on 12/08/2011 for the course GEO 121 taught by Professor Staff during the Fall '11 term at North South University.

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Ice Ages - Ice Ages Pleistocene 3 M.y. Permian 250-220 M.y....

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