Oldest Life on Earth Unearthed in 3.48-Billion-Year-Old Australian Rocks
The oldest life ever found was dug up in 3.48 billion year old hot spring deposits in the Pilbara region of Western Australia.
According to a report from University of New South Wales (UNSW) Sydney, the new discovery in the Dresser Formation provided evidence that life existed much earlier than previously believed. Before this research, the oldest microbial life on land was about 2.7 to 2.9 billion years old from South Africa.
"Our exciting findings don't just extend back the record of life living in hot springs by 3 billion years, they indicate that life was inhabiting the land much earlier than previously thought, by up to about 580 million years," first author Tara Djokic explained. "This may have implications for an origin of life in freshwater hot springs on land, rather than the more widely discussed idea that life developed in the ocean and adapted to land later."
Two hypotheses can explain the origin of life: that it began in deep sea hydrothermal vents or on land as a version of Charles Darwin's "warm little pond".
"The discovery of potential biological signatures in these ancient hot springs in Western Australia provides a geological perspective that may lend weight to a land-based origin of life," Djokic added.
The Pilbara hot spring deposits were exceptionally well-preserved, and the team of scientists were able to determine that they were formed on land. Stromatolites - layered rock structures created by ancient microbes - were present in the deposits as well as other signs of early life.
Aside from improving the understanding of early Earth, the findings of the UNSW team also provided potentially useful data for the search of life on Mars. Because the Pilbara deposits are about the same age as hot spring deposits on the red planet, life may also lie preserved in Martian hot springs.
The study was published in the journal Nature Communications.