Dresser Formation, North Pole Dome, Pilbara

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A sequence of about 3.48 billion-year-old cherts and barites in the North Pole Dome of the Pilbara Craton in Western Australia, and the location of what is generally treated as the oldest widely accepted evidence of life. Its strength relative to the Greenland and Quebec claims is that the Pilbara rocks are barely metamorphosed — they were never cooked to the point where mineral textures could imitate biology — and that several independent lines converge: domical and coniform stromatolite morphologies, laminated microbial textures, sulfur isotope signatures consistent with microbial sulfate metabolism, and an interpretable depositional setting of a shallow, hydrothermally influenced volcanic basin. The nearby Strelley Pool Formation, roughly 3.43 billion years old, carries an even more elaborate reef-like stromatolite assemblage. Neither yields a fossil cell that anyone can point to; the case is built entirely on structures a community of organisms would leave and geology alone should not.