Mars has undergone thousands of super volcanic eruptions over 500 million years

On Mars, there is a region that astronomers suspected to be the land of a few explosive super-volcanoes. They not only just confirm it. But still to discover that they were at the origin of thousands of violent eruptions.

In the Solar system, some volcanoes undergo eruptions of colossal power. Eruptions that release masses dust and gas blocking the light of Sun. With an impact on the weather of their host planet for decades. And it is precisely the traces of such massive eruptions that NASA astronomers just noted in a region of northern Mars that they call Arabia Terra.

According to them, the red planet has even been the scene of thousands ofexplosive eruptions massive over a period of 500 million years. All about four billion years ago. “Each of these eruptions could have been enough to disrupt the climate of Mars, specifies Patrick Whelley, geologist to Goddard Space Flight Center, in a NASA press release. Now modelers need to get to work trying to understand the overall impact this episode may have had. “

What caught the eye of researchers was the identification of seven structures resembling calderas in the region ofArabia Terra. A caldera is a flat-bottomed depression located in the heart of super volcanoes. The result of an eruption that emptied the Magma chamber. And on Mars, these depressions were considered until then as impact craters of meteorites.

Massive volcanic activity betrayed by ash

To get a clear idea of ​​their true nature, NASA researchers set out not to search for the volcanoes that could have been at the origin, but the ashes carried by the wind that their eruptions would inevitably have left behind. They identified them thanks to the spectrometer of Mars Reconnaissance Orbiter (MRO). Then, using the cameras on board the probe, the astronomers established a 3D topographic map ofArabia Terra. A map surprisingly well following models predicting the distribution of ash on the ground for hundreds of thousands of kilometers after explosive super-eruptions.

According to the volume From each caldera identified, the researchers then estimated the number of eruptions needed to produce the ash mat they observed. The equivalent of no less than 400 million Olympic rock pools in fusion and gas first ejected into the tunes. Result: it took several thousand eruptions over a relatively short geological time.

Researchers are now wondering about the distribution of volcanoes on the surface of Mars. Other types of volcanoes have indeed already been discovered on the Red Planet. But the region ofArabia Terra seems to be the only one carrying such explosive volcanoes. On Earth, these volcanoes are scattered. Perhaps the result of traveling around the Globe with the tectonic plates. To be continued …

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