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takyon [soylentnews.org] writes:

Scientists have found fossilized microbes that they have dated to between 3.77 and 4.28 billion years old [bbc.com]:

The fossil structures were encased in quartz layers in the so-called Nuvvuagittuq Supracrustal Belt (NSB). The NSB is a chunk of ancient ocean floor. It contains some of the oldest volcanic and sedimentary rocks known to science.

The team looked at sections of rock that were likely laid down in a system of hydrothermal vents - fissures on the seabed from which heated, mineral-rich waters spew up from below. Today, such vents are known to be important habitats for microbes. And Dr Dominic Papineau, also from UCL, who discovered the fossils in Quebec, thinks this kind of setting was very probably also the cradle for lifeforms between 3.77 and 4.28 billion years ago (the upper and lower age estimates for the NSB rocks).

[...] At present, perhaps the oldest acknowledged evidence of life on the planet is found in 3.48-billion-year-old rocks in Western Australia. This material is said to show remnants of stromatolites - mounds of sediment formed of mineral grains glued together by ancient bacteria. An even older claim for stromatolite traces was made in August last year. The team behind that finding said their fossil evidence was 3.70 billion years old. [...] Part of the interest in ancient life is in the implication it has for organisms elsewhere in the Solar System. "These (NTB) organisms come from a time when we believe Mars had liquid water on its surface and a similar atmosphere to Earth at that time," said Mr Dodd. "So, if we have lifeforms originating and evolving on Earth at this time then we may very well have had life beginning on Mars."

Evidence for early life in Earth's oldest hydrothermal vent precipitates [nature.com] (DOI: 10.1038/nature21377) (DX [doi.org])

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