Last updated May 10, 2017 at 5:03 pm
The origins of life bubble to the surface in the Pilbara region of Western Australia.
New finds, published in the journal Nature Communications, by palaeontologists from the University of New South Wales have pushed back the emergence of terrestrial life by over half a billion years to some 3.48 billion years before the present. This new fossil evidence suggests a new theory on the origins of life on Earth and may help with the search for life on Mars.
The researchers were studying exceptionally well-preserved deposits from the Dresser Formation in the Pilbara region of Western Australia. In that rock unit they found the remains of ancient hot spring deposits that would have formed on land rather than on the sea floor. The deposits were identified as having been formed on land because of the presence of the mineral geyserite. Previously, the oldest known geyserite had been identified from rocks a mere 400 million years old.
Ridges in the Dresser Formation in the Pilbara Craton of Western Australia that preserve ancient stromatolites and hot spring deposits. Credit: Kathleen Campbell
Within these hot spring deposits, the researchers also found stromatolites – layered rock structures created by communities of ancient microbes. There were other signs of early life including microfossils, distinctive microbial textures and well-preserved bubbles that were probably trapped in a sticky, organic substance.
Spherical bubbles preserved in 3.48 billion year old rocks in the Dresser Formation in the Pilbara Craton in Western Australia provide evidence for early life having lived in ancient hot springs on land. Credit: UNSW
Previously, the world’s oldest evidence for microbial life on land were 2.7- 2.9 billion year old ancient soils from South Africa rich in organic matter. So this new find not only pushed back life on land by around 580 million years, it also pushes back our knowledge of life in hot springs by around three billion years.
This new find may have implications for the ultimate origin of life. It suggests that life may have arose in freshwater hot springs on land, rather than the more widely accepted idea that life developed in the ocean around what are known as deep sea hydrothermal vents.
And it’s not just a new theory for the origin of life on Earth that comes out of these amazing finds. The researchers also claim that these rocks have major implications for the search for life on Mars. It is known that Mars has ancient hot spring deposits of a similar age to those in the Pilbara.
- Link to original research article: nature.com/articles/ncomms15263