3.3 billion-year-old rocks are found to have evidence of life

The hi-tech methods could also be employed in future to search for signs of extraterrestrial life

- By Ed Stoddard

Top: Dr Frances Westall (left) and an assistant from the Centre de Biophysique Moleculaire in France investigate some of Earth's oldest rocks at the Barberton Greenstone; Above: Dr Westall (right) and colleagues at the site.

(Supplied/Courtesy Frances Westall)

Chemical evidence of life has been uncovered in South African rocks that are 3.3 billion years old, doubling the timelines for this window into our deep past and charting a new scientific trail that could help to detect the spoor of life on other planets.

The findings, presented by scientists on Monday, 17 November, in the journal Proceedings of the National Academy of Sciences, push back the dating on this front by an astonishing 1.6 billion years. The earliest such traces had previously been detected in rocks 1.7 billion years old.

Spearheaded by scientists from the Carnegie Institution for Science in collaboration with several other institutions, the study, which combined state-of-the-art chemistry with artificial intelligence (AI), also found evidence of oxygen-producing photosynthesis 2.5 billion years ago, extending this timeline back by 800 million years.

This finding was yielded from South African geology — the 3.3-billion-year-old evidence of life from the Josefsdal Chert near Barberton in Mpumalanga, while the earliest known evidence of photosynthesis was found in the Gamohaan Formation near Kuruman in the Northern Cape.

"Besides helping find evidence of Earth's earliest life, this work advances a potential way to identify traces of life beyond our planet," Carnegie Science said in a statement announcing the findings.