In Greenland, a recent discovery could, if confirmed, push back the first traces of life on Earth by 220 million years. Indeed, Australian researchers have just discovered traces of microbial activity dating back 3.7 billion years in a fossilized form.
» It’s crazy ! We didn’t think such clues could have survived for so long. This indicates that 3.7 billion years ago, Earth was no longer some kind of hell. It was, on the contrary, a place where life could thrive » these are the enthusiastic words of Allen Nutman, professor at the Australian University of Wollongong, who participated in the work published in the journal Nature. This discovery was made by Australian geologists, and these are stromatolites demonstrating the presence of life forms on Earth 3.7 billion years ago.
» These stromatolites are created by colonies of microorganisms. In those remote times, therefore, there was a kind of collaboration. Life already had a long history! adds Allen Nutman, suggesting that life may have appeared even earlier. Stromatolites are limestone rock formations forming cauliflower massifs and formed of superimposed sheets. Those discovered in the greenstone belt of Isua, an island located southwest of Greenland, measure from one to four centimeters in height.
Biological analysis of these stromatolites, powerful biological indicators, has indeed shown traces of microbial activity dating back 3.7 billion years, 200 million years older than previous records found in rocks. from Australia or South Africa, and especially only about 800 million years after the formation of planet Earth, 4.6 billion years ago.
A discovery which also has another significance, since the conditions for the appearance of life at that time are quite similar to those which reigned then on Mars. » At the time we are talking about, the Earth was a world apart: black continents without animals and plants and dark green oceans, rich in iron. And to top it off, an orange sky, the atmosphere of the time being poor in oxygen explain the researchers. » Suddenly, Mars could be much more promising than before in terms of its potential as a repository of past life.“, adds Abigail Allwood, of the California Institute of Technology.
Source: nature, world