Marchant, Lewis and Ashworth, who often spend months living in tents in the Dry Valleys doing their research, all said that the fossil finds stretch their imagination about how the Antarctic continent once looked.
"The fossil finds allow us to examine Antarctica as it existed just prior to climate cooling at 13.9 million years ago. It is a unique window into the past. On land, there are very few places on Earth that contain sediment of this age, and none are as well preserved as those found in the Dry Valleys," Marchant said. "The sediments allow reconstructions of alpine glaciers, tundra and lakes, all in remarkable detail. To study these deposits is akin to strolling across the Dry Valleys 14.1 million years ago."
"What we're basically looking at," Lewis added "is the last hint of vegetation in the Dry Valleys." "The fossil finds and dating of volcanic ash show that roughly 14.1 million years ago, the area was home to tundra, "wet" glaciers typical of those of the mountains of Tierra Del Fuego in the high southern latitudes, and seasonally ice-free lakes. The beds of those long-gone lakes contain layers of sediments where detritus such as dying plants and insects would have settled and been preserved."
"And it's within these ancient lake beds that we found the fossils," said Lewis.
Ashworth's and the other paleoecologists' research shows that the lakes supported mosses and diatoms, and the surrounding margins were 'minimally colonized' by insects and shrubby vegetation."
At 14.1 million years ago, the Dry Valleys were relatively warm. By 13.9 million years ago, everything was different. The transition brought the Dry Valleys from a climate like that of South Georgia to one that has Mars as a close analog.
Tom Wagner, program director for Antarctic Earth Sciences in NSF's Office of Polar Programs, added that "Lewis, Marchant and Ashworth discovered the last bit of life on the Antarctic continent. It was hang
|Contact: Peter West|
National Science Foundation