Scientists from the University of New South Wales have discovered fossil evidence of early life in 3.48 billion-year-old hot spring deposits in the Pilbara of Western Australia – a region known for its large mineral deposits – representing the earliest known existence of hot springs. hot inhabited on Earth.
Previously, the world’s oldest evidence for microbial life on earth came from 2.7 to 2.9 billion-year-old deposits in South Africa that contained ancient soils rich in organic matter.
“Our exciting findings not only extend back the record for life living in hot springs, but indicate that life was inhabiting the earth much earlier than previously thought, around 580 million years earlier, ” says Tara Djokic. , leader of the work.
“This may have implications for the origin of life in freshwater hot springs on land, rather than the more widely discussed idea that life developed in the ocean and later adapted to land,” explains Djokic.
It is the oldest terrestrial living being ever discovered
The researchers studied exceptionally well-preserved deposits that are approximately 3.5 billion years old in the ancient Dresser Formation in the Pilbara Crater of Western Australia. They identified the presence of geyserite – a mineral deposit made up of high-boiling fluids, rich in silica, found only in a terrestrial hot spring environment. Previously, the oldest known geyserite had been identified from rocks about 400 million years old.
They also discovered stromatolites – layered rock structures created by communities of ancient microbes – as well as other signs of early life, including fossilized microstromatolites or well-preserved bubbles , which were likely trapped in a sticky (microbial) substance to preserve the shape of the bubble. .
“ This shows a diversity of life in freshwater, on land, very early in Earth’s history, ” says Martin Van Kranendonk, director of the Australian Center for Astrobiology and the University’s School of Biological, Earth and Environmental Sciences. from New South Wales.
“The Pilbara deposits are the same age as most of the crust of Mars, which makes the hot spring deposits on the red planet an exciting target in our quest to find fossilized life there,” continues the expert. .
“The Pilbara provides us with a rich history of early life on Earth and is a key region for developing exploration strategies for Mars to try to answer one of the greatest enigmas in science and philosophy: Did more than one life arise? time in the universe? “, ends Van Kranendonk.
The study has been published in the journal Nature Communications.
Image Credit: UNSW
