The Oldest Evidence of Life On Earth Was Found in Australia

The latest study conducted on a 3.4 billion-years-old fossil has concluded that this is the “world’s oldest evidence of life.”

Back in 2011, in the Western Australian desert, scientists discovered in the Strelley Pools formation microfossils which proved to be from ancient bacteria that lived 3.4 billion years ago. This is an unbelievable find because Earth is almost 4.5 billion years old, making the fossils the oldest ones ever discovered.

In a recently published study in the journal Geochemical Perspectives Letters, the authors explain the importance of their find.

Inside the fossils, there were traces from an ancient bacteria. An international team of researchers started chemically analyzing the microfossils to learn more about them. Using complicated techniques like Raman microspectroscopy, synchrotron-based X-ray absorption spectroscopy, focused ion beam and many other methods, the researchers had a detailed analysis of the chemicals contained in the fossil.

These Are the Oldest Fossils Yet Discovered

Then, they compared the old fossils with 1.9 billion-year-old microfossils from Canada (found in the Gunflint Formation). The team also compared their results to modern bacteria.

The results were intriguing. The Strelley microfossils were in a better conservation state compared to the recent Gunflint fossils. Considering the degradation state of all three types of bacteria, the researchers found that they all had the same absorption features, meaning that all fossils – especially the oldest ones – are evidence of life:

“We demonstrate that the elemental and molecular characteristics of these 3.4 Ga microfossils are consistent with biological remains, slightly degraded by fossilisation processes,” said MIT biogeochemist and researcher Julien Alleon.

He also noted that the Strelley fossils were very well preserved and that they were exposed to very high temperatures for long periods of time:

“And yet we are still able to see signs of their original chemistry. This is a step forward to confirming that these are indeed the oldest fossils yet discovered.”

Geochemist and researcher at the Australian National University, Vickie Bennett explains that these new types of analyses provided “compelling evidence that the cherts contain biogenic microfossils.”