Mars had supervolcanoes early in his training - Público.pt

Some of the huge craters on a plateau of Mars may be, after all, the result of the eruption of supervolcanoes, concludes a study published Thursday in the journal Nature .

While analyzing depression Eden Patera located in Arabia Terra highlands in the northern hemisphere of the planet, Joseph R. Michalski, researcher at the Natural History Museum of London and the Planetary Science Institute in Tucson, United States, found that he lacked the typical characteristics of a crater of a meteorite impact, as the roughly circular shape, the raised edge and elevations central. But had characteristics of a caldera as a deep (1.8 kilometers max) compared with the diameter (85 kilometers max.)

Faced with these questions, the researcher consulted volcanologist Jacob E. Bleacher, the Goddard Space Flight Center of NASA, which detected signs of seepage lava crevices formed by the movement of magma below the surface and several breakdowns that led to the formation of the caldera.

After all, Eden Patera is a gigantic ancient volcano. This discovery prompted scientists to the possibility of other depressions, classified as impact craters are actually boilers supervolcanoes that have been active for more than 4000 million years on the Martian surface. Then identified as volcanoes structures such as Oxus Patera and Siloam Patera.

supervolcanoes are not grandiose by its size (not too big cones form), but by the power of the explosions and the amount of ejected material (lava, ash and rock fragments). On Earth, supervolcanoes, like Yellowstone (United States), which erupted 640,000 years ago, may expel more than one million cubic meters of material (or 1000 cubic kilometers), which is ten thousand times more than the material ejected by the eruption of the Eyjafjallajökull volcano in Iceland in 2010. And that conditioned air traffic.

On Mars, as on Earth, the eruptions of these supervolcanoes have affected climate, atmospheric composition and evolution of the planet itself. Researchers believe that the materials may be expelled from the planet cooled by blocking the arrival of the solar radiation on the ground. But on the other hand, the emission of greenhouse gases from the volcano would have contributed to the warming of Mars.

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The influence of these volcanoes temperature and in the presence of gases such as carbon dioxide and water vapor in the atmosphere may be created ideal conditions for the existence of liquid water (rivers and lakes), giving an opportunity to the emergence of life on the planet.

is very difficult to identify the existence of supervolcanoes because they occurred long ago, and are subject to change at the surface, and because there was violence of eruptions destroyed the volcanic cone (if one existed). Volcanoes effusive (non-explosive) which will form their cones rather wide by seepage of the lavas, since they are easier to identify.

Mount Olympus, also on Mars, but along the equator, is one such effusive volcanoes. Despite currently being extinct, is clearly visible, or was not the largest volcano in the solar system, with 25 kilometers high (three times higher than Mount Everest on Earth) and 624 km wide.