James Ashworth, 11 November 2022.

Excerpt:

>Structures found in 3.48-billion-year-old Australian rocks are the oldest evidence of life on Earth.

>Detailed analyses of geological samples from the Dresser Formation conclude that, despite previous scientific controversy, they represent fossils formed by early life and could provide hints of what scientists should look for on Mars.

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>Around 3.5 billion years ago, the area where Western Australia's Dresser Formation is now found would have featured shallow lagoons fed by water enriched in nutrients due to volcanism and hydrothermal activity.

>These lagoons are believed to have been inhabited by photosynthetic organisms, with the fossilised remains of the structures they formed preserved within the sedimentary rocks of the Dresser Formation.

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>On Mars, very similar habitats could have existed more than three billion years ago when the planet is considered to have been habitable.

>If life ever existed on Mars, it is possible that similar fossilised remains could be found.

>In a new study, published in the journal Geology, researchers examined samples from the Dresser Formation in greater detail than ever before.

>Not only do they add weight to arguments that these structures represent some of the earliest traces of life on this planet, but also provide a dry run of the process that will be performed on Martian rocks when they are returned to Earth.

Geology, DOI 10.1130/G50390.1