3500 – 3400 million years ago

Year twelve
The oldest known fossils?

The oldest known fossils?

When Earth was about 12 years old (about 3400 million years ago) the Apex Chert of Warrawoona, Western Australia, formed.

Fossilised bacteria have been reported in these rocks, and if that is correct, they would be the oldest known fossils. However, there are some palaeontologists who now believe that they are not fossils at all, but minerals.

Are these fossil bacteria joined together forming a long chain of cells called a filament? Or are they due to mineral growth? Debate continues.

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