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Ancient rock remains reveal signs pointing to earliest life on Earth

Oct 07, 2019

Ancient rock remains in the remote Pilbara region of Western Australia hold the key to analysing some of the earliest signs of life on Earth, according to a new study by The University of Western Australia in collaboration with a global team of scientists.

The findings, published in the journal Geology, point to the existance of ancient life on Earth, after researchers uncovered exceptionally preserved microbial remains inside samples of rock from the Dresser Formation, in the Pilbara.

Associate Professor Marco Fiorentini from UWA’s School of Earth Sciences said the fossilised microbial structures were found in ancient stromatolites, which are sedimentary rocks that are formed by natural growth over time.

“These new pieces of critical evidence we have uncovered represent a truly exciting step forward, enabling us to prove the existence of ancient life on our planet,” Professor Fiorentini said. “This puts to rest a 40-year long debate on the origin of these stromatolites.

“Results from this research provide ‘smoking gun’ evidence that bacteria indeed thrived in these ancient rocks, showcasing how some of Earth’s earliest life forms functioned.”

The samples, which include preserved organic matter discovered inside pyrite crystals, were collected using a specialised drilling technique and analysed using state-of-the-art equipment at UWA.

“The diverse range of analytical tools available at UWA enabled us to image the presence of these bacteria at the nanometre scale, using high-powered electron microscopy, spectroscopy and isotope analysis,” Professor Fiorentini said.

The new clues gathered during the research would prove to be instrumental in analysing early life and provide helpful insight into the search for life on the planet Mars.

“It’s difficult to find what you are not looking for,” Professor Fiorentini said.  “This research has helped us gain an understanding that we can now apply to the search for life on Mars, by analysing similar environments on the distant planet.”

An ongoing study, funded by the Australian Research Council in response to the findings, aims to analyse the environmental conditions where these ancient microbial colonies thrived.

Stefano Caruso, a research associate from UWA and The University of New South Wales, said the ongoing research would focus on establishing the role of metals and other key geochemical elements during the establishment of early life at the Dresser Formation.

“The results obtained from the ongoing study at the Dresser Formation can be used as a blueprint to inform futher research focusing on the analysis of Martian rocks, to ultimately search for clues of early life in the wider solar system,” Professor Fiorentini said.

Media references

Nicholas Smith (UWA Media Officer)