Illustration de la Terre primitive. © Nasa

Life on Earth was already diverse more than 3.7 billion years ago!

at the beginning of XXAnd In the last century, there was reason to believe that planets and, in fact, planetary systems must be rare in the observable universe. We now know it’s almost inevitable Main sequence stars. What about the emergence of life on Earth? A huge coincidence with a very slow evolution or, conversely, an inevitable and very fast process, probably not only at the beginning of the Archean period 4 billion years ago, but already only a few hundred million years ago after the birth of the blue. Planet during Hadean?

In 2017, the team that already includes Dominic Papineau is currently working at Planetary Science Center from’UCL London Center for Nanotechnology, great ad. Futura talked about it in an article we discuss below that was based on a publication in the famous newspaper temper nature.

Earth science researchers studied rocks from the Nuvvuagittuq supracrustal belt (Nuvvuagittuq Supracrustal Belt or NSB in English) located in Quebec. The rocks were collected in 2008 by Dominic Papineau. The NSB is also referred to as the Nuvvuagittuq Greenstone Belt. This rock formation is located on the eastern shore of Hudson Bay, 40 km southeast of Enocjuac, Quebec, and consists of volcanic rocks mafic and ultramafic associated transformations sedimentary rocks It is one of the oldest known sites on earth.

Presentation of the discovery of possible microfossils that are at least 3.75 billion years old. For a fairly accurate French translation, click the white rectangle at the bottom right. The English translation should then appear. Then click on the nut to the right of the rectangle, then click on “Subtitles” and finally on “Translate automatically”. Choose “French”. © UCLTV

It is estimated that there are rocks that could be between 3.75 and 4.28 billion years old. However, according to Dominique Papineau and colleagues in 2017, some of these rocks also contain chemical structures and compounds that seriously suggest they are microfossils. If this is indeed the case, life has already existed for at least 3.75 billion years on Earth, probably appeared 4 billion years ago, and is rapidly evolving to give the various microfossils that one seems to notice in NSB rocks.

This contrasts with the current paradigm which holds that life could not have appeared until the beginning of the Archaean, and that it did not have time to evolve much to give truly diverse forms.

Vital or abiotic structures?

Of course, possible microfossils have been found in rocks similar to those of the NSB for decades, which indicates an environment similar to that of NSB. hydrothermal vents Today’s oceans, an environment in which life is believed to have emerged through exploitation chemical synthesislong before the discovery of Photosynthesis Then use the oxygen.

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Serious doubts have long been raised about the biological origin of these microfossils or the associated chemical effects (see explanations Herve Martin below), and those of the National Security Office of Quebec were no exception to the rule. But today, Dominique Papineau and his colleagues are returning to the topic with new arguments to try to convince the skeptics as we can read with a publication in science progress.

Have you ever seen dinosaur fossils? It is hard to suspect its existence or to imagine that it may have been produced in a non-vital way! But what kinds of traces did bacteria leave on Earth over 3.5 billion years ago? How do you find the oldest traces of life on Earth? With Hervey Martin, the sadly deceased geologist, explanations in 10 minutes. © French Society of Exobiology

It was a matter of trying to prove that the filamentous structures already observed – reminiscent of groups Microorganisms Already diversified by sudden rapid evolution over 3.75 billion years ago – they weren’t abiotic products, like seep deposits from rich waters iron heated by the silhouette In ancient rocks but after their formation.

The structures observed are actually made of hematite, a form of iron oxide or Rustand imprisoned quartz. Their study was repeated by cutting new sections to the thickness of paper (100 .). micron) in rocks collected in 2008. It was then easy to make comparisons with what can be observed bacteria Oxidized iron is located near the systems Breathing Thermal water today.

As described in the UCL press release accompanying the publication of the article by Dominique Papineau and colleagues, these researchers were clearly able to show that we were in the presence of truly equivalent forms of twisted filaments, with parallel branching structures and deformed domains in existing hydrothermal vent rocks, for example near underwater volcano Loihi near Hawaii.

Monitoring techniques are used in particular X ray Powerful expert image processing Computers He asserted that the hematite filaments were undulating, twisted, and contained carbon Organic, characteristics shared with modern iron-eating microbes as the UCL press release explains.

From all these data, the researchers concluded that, according to them, hematite structures cannot be formed by compressing and subsequently heating rocks, using Transformation that would have operated for billions of years after the end of the Hadean.

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Written by Hervé Cotten, Astrochemist, University Professor, Lisa, Université de Paris Est Créteil/University of Paris/CNRS Discover website Are we alone in the universe? You may have already asked yourself… We can find answers in movies, literature or science fiction comics and our imaginations are populated by extraterrestrial creatures! But what does science say about this? AstrobioEducation invites you to discover exobiology, an interdisciplinary science that aims to study the origin and research of life elsewhere in the universe. Through an educational journey divided into 12 phases, researchers from different disciplines will help you understand how science works to answer fascinating questions about the origins and research of life elsewhere than on Earth. © French Society of Exobiology

Origin of life: Perhaps the oldest fossils were found in Quebec

Article from Laurent Sacco Posted on 02/03/2017

For decades, geologists have discovered intriguing structures that they suggest are microfossils over 3.5 billion years old. However, these results are often disputed. The latest was above all records: the presumed microfossils were found in Quebec, in rocks that are at least 3.77 billion years old.

Earth’s geological records are becoming increasingly rare and increasingly difficult to decipher as one goes back in time from the Archaean, towards the Hades. So it is difficult to determine when a file isthe emergence of life On the ground.

However, in 2008, researchers made a startling announcement. According to them, they showed that the rocks along the coast of Hudson Bay in northern Quebec – in an area called the “Nuvvuagittuq Greenstone Belt” (Nuvvuagittuq Supracrustal Belt, or NSB) – were roughly in place 4.3 billion years ago, just a few years later. Hundreds of millions of years only from the formation of the Earth.

Now, an international team of Earth science researchers has published an article in temper nature Announcing the discovery of traces of life forms, in rocks in the same region of Quebec, which may be at least 3.77 billion years old, and possibly more: up to 4.3 billion years. If so, it would be the oldest evidence of living organisms known to date on Earth.

Thermal springs are the origin of life?

In this case, the researchers believe that they have discovered microfossils, that is, the fossilized remains of microorganisms. Previously, the record was kept by similar remains found in Western Australia with an estimated age of 3.46 billion years (see also the article below on the possible discovery of fossilized remains from Stromatolites built by cyanobacteria 3.7 billion years ago). The putative Nuvvuagittuq fossils appear as tubes and filaments of hematite (a mineral based on iron oxide) located inside layers made of quartz.

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If confirmed, this discovery will be interesting in more ways than one:

  • Indeed, you should know that the Nuvvuagittuq Greenstone belt contains sedimentary deposits and other rocks that indicate that it formed in a volcanic region similar to the one we observe today. hot springs Hydrothermal. This can only strengthen in their faith those who believe that life appeared in these hot springs.
  • Finally, microfossils that are at least 3.77 billion years old, and possibly a few hundred million years older, indicate that life appeared very quickly on Earth.
  • As a bonus, we can also consider that all of this brings flour to the mill for those who think life could have come along so quickly. Marswhen similar conditions prevailed there and there were abundant areas ofliquid water and one volcanoes Energetic.

Bacteria or metal structures?

However, caution is required. This is not the first time that structures reminiscent of the remains of filaments made up of fossilized cells have been discovered. In many cases, it has been realized that these structures may have been generated by abiotic processes. It happened with the so-called microfossils discovered in Australia.

Researchers are well aware of this. This is why they put forward several arguments in support of the thesis that they are indeed microfossils, and not hematite concentrations resulting from changes in the pressure and the temperature to which the rocks containing it were exposed.

These arguments are:

  • First, tubes and filaments have mitotic properties similar to those of tubules and filaments formed by chemotrophic bacteria fromoxidation Iron is found today near hydrothermal vents.
  • Finally, we find graphite and the metal Carbonates and phosphates also associated with living forms and their fossilized remains.

We’re at least betting that research will proliferate on Nuvvuagittuq, particularly the ones that are being exogenous biologists Interested in the environment of Mars.

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