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Abstract GOING TO THE COLDEST PLACE ON EARTH TO LEARN ABOUT THE HOTTEST EVENT IN EARTH’S HISTORY Timothy J. McCoy How did Earth-like planets evolve from a loose pile of cosmic sediments to the molten, layered worlds we know today? This is one of the great unanswered questions for geologists and one for which the 4.5 billion year old record has been erased my melting, plate tectonics and weathering on Earth. As it turns out, Antarctica may hold the answer. For the past 30 years, field parties of the U.S. Antarctic Meteorite Program – a joint venture of the Smithsonian Institution, NASA and the National Science Foundation – have collected more than 15,000 meteorites from the icy plateau of Antarctica. This treasure trove of meteorites includes samples from the Moon, Mars and a myriad of asteroids, both primitive and melted. Among these samples are a small number that record the intermediate stages of the melting of asteroids. With minerals and chemistry similar to the most primitive meteorites, they record evidence of heating and melting. These melts would eventually form the basaltic crusts and metal-rich cores that are the hallmark of Earth-like planets. On some asteroids, this process was stopped midcourse and the evidence is trapped inside these meteorites. Veins of metal, sulfide and basalt offer clues to not just the chemical processes that occurred, but the physical processes the operated during melting and differentiation of Earth-like planets. In this talk, we will examine the evidence for this melting, including some remarkable findings about the ultimate fate of carbon that has startling implications for the origin and detection of life in the Solar System.
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