When did life begin on Earth? The Isua rocks in Greenland have become a key evidence in this answer as a team of researchers from the University of Wollongong (Australia) has discovered in them the oldest fossil on Earth. They are several stromatolites (structures formed by the sedimentation of microorganisms) that date back 3,700 million years ; a time when the Earth was bombarded by asteroids and was still in the formation phase.
These fossils, between one and four centimeters, have been found in metamorphic stones of Isua, southwest of Greenland and exceed by 200 million years what until now were the oldest fossils ever found, stromatolithic structures dating back to 3,500 millions of years old and that had been discovered in Warrawoona (Australia).
It has not been an easy job to find signs of life from the past in these metamorphic rocks of the Isua volcanoes, subjected to great pressures and considerable temperatures, which are also the oldest rocks on Earth. They are deformed, altered rocks; However, the melting of a perennial snow cover brought them to light, allowing such a great discovery.
“ It is rare to find organic remains in fossil stromatolites. They are mostly accumulated carbonates that have been cemented by the disposition of sediments and organisms ”, explains Allen Nutman, co-author of the study.
The results of this research thus consolidate the previous dates of the emergence of life on Earth, dated at 4,000 years.
The study has been published in the journal Nature.
