Last updated March 6, 2017 at 3:25 pm
The world’s oldest fossils have been described in today’s issue of the journal Nature. The microfossils are thought to represent iron-eating bacteria that are at least 3,770 million years old and could have been alive as much as 4,290 million years ago.
Tiny filaments and tubes formed by bacteria were found encased in quartz layers of rocks from the Nuvvuagittuq belt in northeastern Canada. These rocks are thought to have formed around deep-sea hydrothermal vents and they closely resemble bacteria that live in similar locations today. The palaeontologists also found iron oxide granules and carbonate rosettes in these rocks which also indicate other biological activity, most likely putrefaction.
Layer-deflecting bright red concretion of haematitic chert (an iron-rich and silica-rich rock), which contains tubular and filamentous microfossils. This co-called jasper is in contact with a dark green volcanic rock in the top right and represent hydrothermal vent precipitates on the seafloor. Nuvvuagittuq Supracrustal Belt, Québec, Canada. Credit: Dominic Papineau
The international team included Adjunct Professor Franco Pirajno, a researcher from The University of Western Australia, who contributed his knowledge of similar but much younger fossils from WA’s Eastern Goldfields Region.
“This research paper provides a remarkable insight into the conditions that led to the origins of life on our planet,” he said.
Microscopic iron-carbonate (white) rosette with concentric layers of quartz inclusions (grey) and a core of a single quartz crystal with tiny (nanoscopic) inclusions of red hematite from the Nuvvuagittuq Supracrustal Belt in Québec, Canada. These may have formed through the oxidation of organic matter derived from microbes living around vents. Credit: M.Dodd
The oldest microfossils reported prior to this discovery were 3,460 million years old from Western Australia but some scientists claim that they might not be fossils of once-living organisms. Geological structures known as stromatolites that are made by microbial colonies have also been found in Greenland dating back to 3,700 million years.
- Link to original research article: nature.com/nature/journal/v543/n7643/full/nature21377.html