2020-11-01

There is evidence that extreme life thrived in hot asteroid craters after the dinosaurs went extinct

By yqqlm yqqlm

After the impact destroyed all non-avian dinosaurs, a huge pool of magma appeared under the surface of the earth. New research shows that this hellish basement hosts a biological ecosystem, and this discovery may provide clues to how life emerged in the early stages of the earth’s turbulence.

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Caption:Yucatan Peninsula. 66 million years ago, an asteroid hit the earth and caused a mass extinction event.

About 66 million years ago, when this asteroid hit our unfortunate planet, it created an impact crater 110 miles (180 kilometers) wide, which is now the Yucatan Peninsula. Evidence presented earlier this year showed that the impact also produced a huge underground magma chamber that lasted hundreds of thousands of years, possibly even millions of years. Incredibly, according to new research published today in Astrobiology, this hydrothermal system supports the entire microbial ecosystem.

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The lead author of these two studies, the moon and planet studies LPI geologist David Kling believes that the Chicxulub hydrothermal system may have a glimpse of the conditions when early life on Earth began to appear. Kling’s co-authors are Martin Whitehouse of the Swedish Museum of Natural History and Martin Schmieder of the University of Neu-Ulm, Germany.

At its peak, the Chicxulub magma chamber is about 1.86 miles (3 kilometers) thick, including 33,500 cubic miles (140,000 cubic kilometers) of crust. In contrast, the crater in Yellowstone National Park is nine times smaller than Chicxulub.

Klin and his colleagues found evidence of this hydrothermal system in a rock core pulled from the peak ring of a crater. This is a jagged ring found in some impact craters (here Good example). With the support of the International Continental Scientific Drilling Program and the International Ocean Discovery Program, approximately 33,000 pounds (15,000 kilograms) of rock were drilled from a depth of 0.81 miles (1.3 kilometers).

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Scientists have once again studied Chicxulub ) Sample material, found a small sphere of pyrite, called pyrite. The sulfur isotope analysis of these feldspars (the diameter is only one millionth of a meter) pointed out that there is a”thermophilic colony of reducing sulfate organisms”, in other words, it is a group of thermophilic microorganisms that have a strong influence on sulfate. appetite. This study shows that these microorganisms live in porous, permeable rocks underneath the crater, and feed on sulfate transported through the rocks. This material is provided by the hydrothermal system produced by the impact.

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As the author pointed out, these underground microorganisms use the internal hydrothermal system The chemical reaction that occurs is to survive in mineral-rich water heated by magma. In this process, sulfate is converted to sulfide, which is retained as pyrite. These creatures are no different from some of the thermophilic bacteria and ancient creatures found in Yellowstone today.

This discovery itself is very interesting, but it may explain the early discovery of the Earth, especially in the late stage of the Heavy Bombing (LHB) that ended about 3.8 billion years ago. During this period known as the Hadean, the Earth was regularly hit by large asteroids, and the surface was completely chaotic and probably uninhabitable. However, some of the earliest life forms on Earth can be traced back to 3.5 billion years ago, or even 3.77 billion years ago.

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Klin and his colleagues speculate that Chicthulhu The conditions under the Chicxulub crater may be similar to those found during the LHB period, and similar extremophiles may have disappeared long ago. More importantly, previous evidence shows that &34; the earliest creatures on earth are thermophilic (thermophilic) and hyperthermophilic (really truly thermophilic”), so”life originated in impact craters”It seems to be”reasonable.” As the author wrote in a two-page summary, explain &34;the origin of impact of the life hypothesis&34;.

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Okay, great stuff, but let’s take a deep breath and consider some important caveats. In Chicxulub The apparent remnants of life seen in this may not actually be life. Other scientists may look at the same sample and see purely non-biological processes at work, and it is usually not surprising that such claims are made. Moreover, the late Cretaceous The environmental conditions of the Haad people are very different (for example, the earth is full of life), therefore, the Chicxulub hydrothermal system may not be a good simulation of the early earth.

More work needs to be done to support the hypothesis of influence origin, including more fossil evidence and a basic understanding of the chemical processes that produce self-replicating molecules, namely RNA and DNA. Nevertheless, we can still be surprised to find that we The earliest ancestors may have appeared in an underground cauldron that was stirred by an asteroid impact.