A team led by the University of Wollongong’s Professor Allen Nutman has discovered the earliest evidence of diverse life on earth – a find which will “turn history on its head”, according to one investigator.
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In a remote area of Greenland, the Australian team unearthed a find which would show life on Earth emerged rapidly in the planet’s early years.
A study published in the journal Nature describes the 3.7 billion-year-old stromatolite fossils which were found in the world’s oldest sedimentary rocks, in the Isua Greenstone Belt along the edge of Greenland’s icecap.
The discovery pushes back the fossil record to near the start of the Earth’s geological record and points to evidence of life on Earth very early in its history.
Professor Nutman, from UOW’s School of Earth and Environmental Sciences, said the Isua stromatolite fossils predated the world’s previous oldest stromatolite fossils – which were found in Western Australia – by 220 million years.
“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. “This indicates that as long as 3.7 billion years ago microbial life was already diverse. This diversity shows that life emerged within the first few hundred millions years of Earth’s existence, which is in keeping with biologists’ calculations showing the great antiquity of life’s genetic code.”
Co-lead investigator Associate Professor Vickie Bennett, from the Australian National University, said their study provided a new perspective into the history of the Earth.
“This discovery turns the study of planetary habitability on its head,” Professor Bennett said. “Rather than speculating about potential early environments, 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.”
The Isua stromatolites were exposed by the recent melting of a perennial snow patch.
This discovery turns the study of planetary habitability on its head.
- Associate Professor Vickie Bennett