Oldest fossils point to thriving life on young Earth

Australian researchers have found the world's oldest fossils, revealing that diverse life forms thrived on Earth 3.7 billion years ago. Co-lead investigator Associate Professor Vickie Bennett from The Australian National University (ANU) said the research on stromatolite fossils found in Greenland provided a greater understanding of early habitats of life on Earth and could have implications for searching for life on Mars. "This discovery turns the study of planetary habitability on its head," said Dr Bennett from ANU Research School of Earth Sciences. "For the first time we have rocks that we know record the conditions and environments that sustained early life. Our research will provide new insights into chemical cycles and rock-water-microbe interactions on a young planet." Co-lead investigator Professor Allen Nutman from UOW said the stromatolite fossils, found in the Isua Greenstone Belt along the edge of Greenland's icecap, predated the world's previous oldest stromatolite fossils from Western Australia by 220 million years. For much of Earth's history life was just single cells, and stromatolite fossils are mounds of carbonate constructed by these communities of microbes. "The significance of stromatolites is that not only do they provide obvious evidence of ancient life that is visible with the naked eye, but that they are complex ecosystems," Professor Nutman said.