The Farrel Quartzite formation in Western Australia has yielded a group of both spheroid and spindle-like microfossils believed to be planktonic organisms.
At 3 billion years old, they are some of the oldest fossils ever found. According to a study in the June issue of the journal Geology, the fossils seem to be similar to ones found in Strelley Pool Formation also in Australia and the Onverwacht Group of South Africa, both of which are approximately 3.4 billion years old.
A team of American and Japanese scientists have identified the fossils as being of biogenic origins (i.e., having once been alive or created as the result of living processes) based on analysis of their stable carbon isotopes. The results also show that the structures found are actual fossils and not “pseudofossils”, created when the environment physically reprocesses organic material already existing in the sediment.
In addition, the information provided by the analysis of the fossils indicates that they were likely autotropic, which means that they made their own food (e.g., many plants currently living make their own food through photosynthesis).
The report points out that if this interpretation of the fossils is correct, then they represent the remains of a “cosmopolitan” biological community “that lasted several hundred million years, starting in the Paleoarchean”. The Paleoarchean was a geologic era that lasted from about 3.6 to about 3.2 billion years ago.
The original article can be found here:
An excellent summary article (along with a photo of one of the fossils) can be found at Sci-News.com here: