pondelok, 8. júna 2009

Ancient Antarctica and the Origin of the Ice Sheets

Geology:
Ancient Antarctica millions of years ago supposedly looked like what the Alps look like today. There were mountains and valleys. It was only about 14 million years ago that the ice sheet covered those up.

"Many studies hint that Antarctica’s ice sheet began to form about 34 million years ago, but where that ice sheet originated and how it evolved have long been mysteries. Now, scientists who used ice-penetrating radar to survey a 30-by-30–kilometer area in East Antarctica report in the June 4 Nature that they may have discovered the birthplace of the Antarctic ice sheet.
The area surveyed during two field seasons — the Antarctic summers of 2005 and 2007 — sits more than 4 kilometers above sea level and is known as Dome A, says Simon M. Mudd, a geomorphologist at the University of Edinburgh. Buried far beneath that region’s relatively flat surface, however, lies a chain of peaks called the Gamburtsev Mountains. The new data, the first collected in the region since an aircraft-mounted radar probed the ice nearby in the 1970s, provides the first detailed glimpse at the subglacial topography there, Mudd says. “The topography here is less well known than the surface of Mars,” he notes."


"Ancient Antarctica, Before the Ice." Science News
Ancient Antarctica

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