Monday, August 22, 2011

Oldest known life-form discovered

22fossil-articleInline-v2.jpgExcerpts of Team Claims It Has Found Oldest Fossils By NICHOLAS WADE, New York Times

A team of Australian and British geologists have discovered fossilized, single-cell organisms that are 3.4 billion years old and that the scientists say are the oldest known fossils on earth.
Their assertion, if sustained, confirms the view that life evolved on earth surprisingly soon after the Late Heavy Bombardment,
a reign of destruction in which waves of asteroids slammed into the primitive planet, heating the surface to molten rock and boiling the oceans into an incandescent mist. The bombardment, which ended around 3.85 billion years ago, would have sterilized the earth's surface of any incipient life.
The claim is also a new volley in a long-running conflict over who has found the oldest fossil.
The new microfossils are described in Sunday's issue of Nature Geoscience by a team led by David Wacey of the University of Western Australia and Martin D. Brasier of the University of Oxford.

The fossils were found in sandstone at the base of the Strelley Pool rock formation in Western Australia.
Examining thin slices of rock under the microscope, they have found structures that look like living cells, some in clusters that seem to show cell division.
Crystals of fool's gold, an iron-sulfur mineral, lie next to the microfossils and indicate that the organisms, in the absence of oxygen, fed off sulfur compounds, Dr. Brasier and his colleagues say.

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