2023-07-16 19:00:00
Called “Northwest Africa (NWA) 13188”, this rock weighing more than 600 grams could be the first meteorite to return to Earth after a long stay in space. Scientists have noted a strong resemblance between this rock and those that form in volcanoes near oceanic tectonic plates. The presence of certain chemical isotopes suggests that the rock has been exposed to cosmic rays from space over tens of thousands of years, the researchers explain.
The glassy “fusion crust” of the rock suggests that it melted when it entered the Earth’s atmosphere and proves that it is not a “false meteorite”, said Jérôme Gattacceca, geophysicist at the National Center on Tuesday. of scientific research, during the Goldschmidt geochemistry conference in France. “We consider that NWA 13188 is a meteorite ejected from the Earth and then returned to the surface”, conclude the authors of the study.
To read: The origin of the Martian meteorite “Black Beauty” discovered in Morocco
Scientists are still trying to find out how this rock got into space. For the moment, they assume that it came from a sufficiently strong volcanic eruption or from a large meteorite that struck the Earth. The team of researchers is studying the volcanic hypothesis. To do this, she checks the concentrations of atmospheric argon contained in NWA 13188, which should be particularly abundant if the rock emanated from a volcanic eruption.
“When you make extraordinary assumptions, you need extraordinary evidence to back them up. I am still not convinced “by this thesis, declared for his part Philippe Claeys, geologist and planetologist. And to clarify: “When you have such a young impact crater, you would have an impact melt that is still “hot and smoky”, it would be very difficult to miss it”.
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