Scientists have found Earth's oldest fossils in Australia and say their microscopic discovery is convincing evidence that cells and bacteria were able to thrive in an oxygen-free world more than 3.4 billion years ago.
The finding suggests early life was sulphur-based — living off and metabolizing sulphur rather than oxygen for energy — and supports the idea that similar life forms could exist on other planets where oxygen levels are low or non-existent.
Hand out picture released by journal Nature Geoscience of Strelley Pool in the remote Pilbara region of Western Australia."Could these sorts of things exist on Mars? It's just about conceivable. This evidence is certainly encouraging and lack of oxygen on Mars is not a problem," said Martin Brasier of Oxford University, who worked on the team that made the discovery.
The microfossils, which the researchers say are very clearly preserved and show precise cell-like structures, were found in a remote part of western Australia called Strelley Pool.
In a study published in the journal Nature Geoscience on Sunday, Brasier's team explained that the tiny fossils were preserved between the quartz sand grains of the oldest shoreline known on Earth in some of the oldest sedimentary rocks ever discovered.
"We can be very sure about the age as the rocks were formed between two volcanic successions that narrow the possible age down to a few tens of millions of years," he said. "That's very accurate indeed when the rocks are 3.4 billion years old."
http://www.msnbc.msn.com/id/44221621/ns/technology_and_science-space
