13 May, 2017
The new find may give credence to Charles Darwin's theory that the origin of life occurred in some "warm little pond".
These are the questions that keep evolutionary biologists awake at night.
"The Pilbara deposits are the same age as much of the crust of Mars, which makes hot spring deposits on the red planet an exciting target for our quest to find fossilised life there."In September 2016, Professor Kranendonk was part of an worldwide team that found what is possibly the oldest evidence of life on earth - 3.7 billion year old fossil stromatolites in Greenland deposits that were laid down in a shallow sea".
The second suggests that life originated on land.
And not only that, it hints at the possibility that life on Earth began not in the ocean, as commonly thought, but on land-based hot springs.
Djokic and her colleagues made their discovery by analysing the incredibly well-preserved deposits of the ancient Dresser Formation in the Pilbara Craton of Western Australia.
The oldest fossil evidence of life on land has been discovered in Australian rocks, potentially extending the known era of land-based life by over 500 million years.
According to the new study, the Dresser Formation contains a telltale signature of land - a mineral called geyserite, which is found exclusively in the surroundings of terrestrial hot springs and geysers.
In those same rocks, researchers found what they call "a suite of microbial biosignatures indicative of the earliest life on land".
A microscopic image of geyserite textures from the ancient Dresser Formation in the Pilbara Craton in Western Australia.
Not only is the find exciting for what it might say about the evolution of early life on Earth, but it also has implications for the search for life on Mars.
"If you're going to look for life on Mars, we know it was preserved on hot springs here on the ancient earth", Djokic said.
Mars' next Rover mission in 2020 may land right next to a Hot Spring the same age as the Dresser spring on earth.
If life can be preserved in hot springs so far back in Earth's history, then there is a good chance it could be preserved in Martian hot springs too, the researchers said.
Importantly, all of these textures are comparable to fossil textures found in modern hot spring settings such as Yellowstone National Park or Rotorua, New Zealand. It was thought that life took another billion years or more to adapt to land, but new fossils discovered in Western Australia may shake up the timeline a bit. The previous holder of this title was 580 million years old.
We also found evidence of gas bubbles that must have been trapped in a sticky substance (microbial) in order to be able to preserve the bubble shape.
UNSW Spherical bubbles preserved in the rocks suggest microbes lived there.
The evidence gathered hints at an ancient Earth that housed volcanic craters, which may have provided the ideal breeding ground for primitive forms of life to emerge billions of years ago.
The scientists reported the biological signs of life which show that hot spring is present along with the rock.
"It's a significant finding and one that re-opens one of the biggest debates in science and that is, did life begin on land or in the sea?" says Professor Campbell from the University's School of Environment.
"The Pilbara deposits are the same age as much of the crust of Mars, which makes hot spring deposits on the red planet an exciting target for our quest to find fossilised life there", he added.