The details of the discovery presented at last month’s Geological Society of America meeting are now part of public domain. A team scouring the Pilbara region of Australia claims to have found evidence of the earliest fossils now known to science. Initial uranium-238 dating places the cyanobacteria fossil remains at 3.49 billion years old, which is just a hair older than the previous recordholders, the 3.45 billion year-old stromatolite structures uncovered back in 2009 that were also from Western Australia.
This would fix the earliest life forms at just over a billion years after the formation of the earth itself.
“It’s not just finding this stuff that’s interesting,” says Alan Decho, a geobiologist at the University of South Carolina’s Arnold School of Public Health. “It’s showing that the life had some organisation to it.” Ridges that crisscross the rocks like strands in a spider web hint that primitive bacteria linked up in sprawling networks. Like their modern counterparts, they may have lived in the equivalent of microbial cities that hosted thousands of kinds of bacteria, each specialised for a different task and communicating with the others via chemical signals.”
Researchers believe these ancient microfossils may give us ideas about what to look for on Mars.
“Ultimately, the fossils found on Earth could help those looking for the building blocks of life on Mars, where NASA’s Curiosity rover has recently found evidence for ancient waterways. Remnants of life on the Red Planet might even be better preserved than they are here on Earth, says Harvard University paleontologist Andrew Knoll. That’s because old terrestrial rocks tend to get banged around by the movement of tectonic plates and cooked by the extreme heat of the planet’s depths. Mars, a planet that’s nearly dead geologically, lacks such tectonic activity.”
External link: Planet’s oldest fossils found in Pilbara, experts say