Earliest evidence of life on Earth 'found' - BBC News:
They are represented by tiny filaments, knobs and tubes in Canadian rocks dated to be up to 4.28 billion years old.
That is a time not long after the planet's formation and hundreds of millions of years before what is currently accepted as evidence for the most ancient life yet found on Earth.
The researchers report their investigation in the journal Nature.
As with all such claims about ancient life, the study is contentious. But the team believes it can answer any doubts.
The scientists' putative microbes from Quebec are one-tenth the width of a human hair and contain significant quantities of haematite - a form of iron oxide or "rust".
Matthew Dodd, who analysed the structures at University College London, UK, claimed the discovery would shed new light on the origins of life.