2021-05-31

Research says asteroid impact craters on Earth provide clues about Martian craters

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Research says asteroid impact craters on Earth provide clues about Martian craters

Unexpectedly, a research team led by the University of Göttingen is now A layer of volcanic ash was found in the asteroid crater. In addition, the research team was able to prove that the ground under the crater is sinking for a long time, which provides important inspiration for exploring craters on Mars, such as those currently being explored by NASA’s Curiosity and Perseverance. Gale Crater and Jezero Crater Basin Lake.

The results of this study have been published in the “Journal of Planetary Geophysical Research”.

Research says asteroid impact craters on Earth provide clues about Martian craters(1)

Until now, people think these Lake sediments have settled on the stable crater ground. Crater deposits on Mars are also believed to be the same, although some of these crater deposits show distinctly sloping deposits. The stratum of these crater fillings appears to be a ring structure on the surface. However, a precise understanding of the basic conditions and temporal relationships of these sediments is very important to reconstruct the chemical development of the crater and the habitability of life forms that may have developed there in the past.

Now, for the first time, researchers have been able to find a layer of volcanic ash in the lake sediments filled with a 330-meter-thick crater on the Richter scale. “This is surprising, because since the circular basin was identified as an asteroid crater, there have been no expected volcanic rocks here,” said first author Professor Gernot Arp from the Geoscience Center of the University of Göttingen.

“The volcanic ash was blown from a volcano 760 kilometers east of Hungary.” His colleague and co-author István Dunkl added: “The age of the volcanic ash can be traced back to 14.2 million years.”< /p>

Research says asteroid impact craters on Earth provide clues about Martian craters(2)

During this period, volcanic ash has been transformed into The nitrogen-rich silicate mineral reveals a surprisingly strong bowl-like geometry: at the edge of the basin, volcanic ash is found on the current surface, while in the center of the basin, it stays at a depth of approximately 220 meters . Subsequent systematic evaluations of drilling and geological mapping have now revealed the concentric arrangement of fillings in the Rees Crater-“outcrops”, with the oldest deposits at the edges and the nearest at the center.

Calculations show that the geometry of this cushion cannot be explained only by the fact that the sediments in the bottom lake have settled. In fact, an additional settlement of approximately 135 meters must be taken into account. This can only be explained by the subsidence of the bedrock of the crater, and the fracture of the bedrock of the crater is several kilometers deep.

Although further research is needed to explain the exact mechanism of the sinking of the bottom of the crater, a simple model calculation can already show that this degree of sinking is basically due to the subsidence of fractured underground rocks. It is possible. This means that it is now possible to better explain the tilted formations in the crater fillings on Mars, at least for those craters that show a close and timely connection between crater formation, water inundation, and subsidence.