In southern Greenland, Ysua, a group of researchers from the University of Wollongong (Australia) have discovered estromatolites of 3.7 billion years. Thus, they have become the oldest remains of life that have been found so far. Estromatolites are made up of carbonate layers produced by microorganisms and the oldest known to date were 3,480 million years old.
The latter are on the Australian coast and have long been the oldest fossils. Those discovered now in Greenland were under the ice and have been exposed to thaw. The researchers have explained that they are found in metamorphic rock, that is, in rocks that have undergone transformations. This has seemed curious, since most of the fossils are found in sedimentary rocks, but the analyses carried out leave no doubt: they come from living organisms. They have probably also determined that they would grow in shallow coastal waters.
Many experts believe that life appeared on Earth 4,000 million years ago, and that this discovery confirms this hypothesis. The study has been published in the journal Nature.