In a discovery that could alter the way in which the origin of life on earth is studied, a team of geogolists have discovered fossils in Greenland that could be as old as 3.7 billion years old according to a latest report in the New York Times.
According to the report, "Experts are likely to debate whether the structures described in the new report were formed biologically or through natural processes. If biological, the great age of the fossils complicates the task of reconstructing the evolution of life from the chemicals naturally present on the early Earth. It leaves comparatively little time for evolution to have occurred and puts the process close to a time when Earth was being bombarded by destructive asteroids.The fossils were discovered four years ago but not publicized while the geologists, a team led by Allen P. Nutman of the University of Wollongong in Australia, checked out their find."
Dr. Nutman said, ""Of course one felt very excited, but we're not the rushing types and we took our time. We kept it secret because we wanted to present it in the most robust way we could manage." The report went on to add some more striking details about the discovery. "The fossils were part of an outcrop of ancient rock that had lost its usual snow cover. The rock layer forming the outcrop, known to geologists as the Isua supracrustal belt, lies on the southwest coast of Greenland and is some 3.9 to 3.7 billion years old.Researchers earlier had claimed that Isua rocks had a chemical composition indicative of life, but critics said this mix of chemicals could have arisen through natural processes.
The new fossils, described on Wednesday in the journal Nature, are the first visible structures found in the Isua rocks. They are thought to be stromatolites, layers of sediment packed together by microbial communities living in shallow water.They are some 220 million years more ancient than the oldest previously known fossils, also stromatolites. Those are 3.48 billion years old and were discovered in the Pilbara Craton of Western Australia.The new report "provides the oldest direct evidence of microbial life," said Gerald Joyce, an expert on the origin of life at the Scripps Research Institute in La Jolla, Calif."
