Tuesday, August 23, 2011

Oldest fossils?

David Wacey/New York Times
This seems to be a year for superlatives in paleontology--well, maybe, if you consider smallest dinosaur to be a superlative. Anyway, Nicholas Wade reports in yesterday's New York Times that "[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." If these are indeed fossils of living organisms, they show that life evolved very early in the earth's history, at a time when, as Wade notes, the atmosphere was rich in methane, and only a few islands rose above the surface of an ocean that was the temperature of a hot bath. The Australian sandstone formation in which these structures (see photo above by David Wacey of the University of Western Australia who, along with Martin D. Brasier of the University of Oxford, discovered them) were found was, 3.4 billion years ago, a beach on one of those islands.