When did life first appear on our planet? Some 300 million years earlier than previously thought, according to a new study led by experts from University College London (United Kingdom) based on the analysis of a rock the size of a fist found in Quebec, Canada, which was It is estimated to be between 3.75 and 4.28 billion years old.
The stone in question is one of the oldest known sedimentary rocks on Earth – it was once a chunk of seabed – and was originally deposited near a hydrothermal vent system, where cracks in the seabed let in waters heated by magma that contained large amounts of iron.
Shortly after the Earth was formed…
Now, after further extensive analysis of the rock (because the previous study was inconclusive about the remains of biological origin or early life on our planet), researchers have discovered within the same rock a larger and more complex structure. consisting of a centimeter-long stem with parallel branches on one side, as well as hundreds of ellipsoids along the tubes and filaments. The rock is pinkish red with dark black veins and white strings running through them. It is rich in silica and bright red iron containing tubular and filamentous microfossils.
In addition to analyzing the rock specimens under various light and Raman (which measure light scattering) microscopes, the research team also digitally recreated sections of the rock using a supercomputer that processed thousands of images from two high-resolution imaging techniques. .
Although some of these structures could have been created by random chemical reactions, the most likely, according to scientists, is that the tree-like stem with parallel branches is of biological origin.
“This means that life could have started as little as 300 million years after the Earth formed. In geological terms, this is fast: about one revolution of the Sun around the galaxy,” explains geochemist Dominic Papineau of the University College London and co-author of the paper published in the journal Science Advances .
The first traces of life on Earth
Until now, the oldest known evidence of life on Earth had been a 3.46 billion-year-old rock found in Western Australia that contained microscopic worm-like fossils. These new findings suggest that a variety of microbial life may have existed on the primordial Earth.
“These findings have implications for the possibility of extraterrestrial life. If life emerges relatively quickly, given the right conditions, this increases the possibility that life exists on other planets,” says the expert.
Referencia: Dominic Papineau, Zhenbing She, Matthew S. Dodd, et al. Metabolically diverse primordial microbial communities in Earth’s oldest seafloor-hydrothermal jasper. Science Advances 13 Apr 2022 • Vol 8, Issue 15 • DOI: 10.1126/sciadv.abm2296
