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Unformatted text preview: Earth 2 Thursday, February 25th, 1999 Announcements: Tests were returned and the second part of our textbook was picked up. Lecture notes: CLIMATE VARIATIONS TENS OF MILLIONS OF YEARS AGO • Shows that the earth's climate was far from stable tens of millions of years ago Cold Climate • Ice covered much of the earth at different points in time--21,000 years ago, 1/3 of the land was covered with ice. 280,000,000 years ago, almost the entire globe was covered with ice • Grooves and striations show up, proving that ice is ripping up material in the environment • Materials are picked up by ice and deposited where the ice melts (tills) • Moraines are found, with unsorted materials and in various sizes • Dropstones , which fall from the surface, disrupt sediments, and later have layers built upon them over time, are found near glaciers • Antartica glaciated 28-35 million years ago, Greenland glaciated 3 million years ago • The world was 3-5 degrees cooler than it is today Warm Climate • Uniformitarianism--explains that the present is the key to the past. An organism that likes a certain climate today probably liked the same...
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This note was uploaded on 02/21/2008 for the course EARTH 002 taught by Professor Eigenbrode during the Spring '99 term at Penn State.
- Spring '99