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[EN VIDÉO] Life on Mars: A review of the most important stages of Mars exploration. The search for life on Mars is a fascinating story full of twists and turns…
If Mars differs from Earth in that it does not have plate tectonics, the two planets share a volcanic past. And Mars certainly has nothing to envy its big blue sister. In fact, there are numerous witnesses of intense volcanism there. The most symbolic is certainly Olympus Mons, the largest volcano in the solar system! This monster rises more than 22 kilometers above the surrounding plain. No earthly structure is even remotely comparable. It demonstrates the planet's ability to produce disproportionate amounts of lava slaves over very long periods of time. But Olympus Mons is not the only large volcanic region on the Red Planet. Elysium Planitia is equally impressive.
Elysium Planitia, second largest volcanic region on Mars
Four large volcanoes mark this plain of lava flows, which extends over an area 3,000 kilometers in diameter. Today the landscape is quiet and the volcanoes are visibly extinct. The absence of any volcanic activity on the planet has long labeled Mars a “dead” planet from a geological perspective. A consideration that, however, could just be a bias related to our (very) short observation period. Because new data shows that Mars may have experienced major eruptions not long ago.
A year ago, an earlier study already revealed the presence of a giant mantle plume beneath the Elysium Planitia region, suggesting that it may have been the source of intense volcanism in the relatively recent past. A new study has now confirmed these results, particularly by indicating the age of the last volcanic events and the amounts of lava ejected.
More than 40 volcanic episodes in the last 120 million years
Thanks to satellite images from HiRISE and georadar measurements (Sharad instrument), scientists at the University of Arizona have documented more than 40 volcanic episodes in Elysium Planitia over the past 120 million years. As a reminder, at the same time dinosaurs and dinosaurs ruled the earth. Each of these episodes produced enormous amounts of lava (up to 16,000 km3) that flowed through large fissures. The youngest is probably no older than a million years. In terms of time, it was yesterday!
So the Red Planet would be far from dead and nothing tells us that a volcanic awakening in the future is impossible.
Dramatic glacier melting
These new results, published in the Journal of Geophysical Research: Planets, are also valuable for astrobiologists. Volcanic eruptions are capable of bringing significant amounts of water to the surface. The magma magma itself contains certain amounts of water, which, when it reaches the surface, evaporates in the atmosphere and falls back to the surface in the form of ice particles. However, the intrusion of magma into the crust can also lead to the melting of water ice trapped underground. Scientists believe it is possible that certain volcanic episodes caused sudden and significant surface flooding.
Understanding how these hydrological and volcanic mechanisms have operated throughout Mars' history is important not only for the search for possible traces of Martian life, but also for future human missions that need to find water resources on this planet. a priori arid.
Mushroom fungi that live on the surface of Mars. Even worse are the noises IngenuityIngenuity makes while flying in the Red Planet's sky. And today, the discovery of recent volcanic activity on the side of Elysium Planitia as a sign that the planet was habitable not long ago. Mars definitely always makes headlines.
Article by Nathalie MayerNathalie Mayer published on May 17, 2021
Mars was “volcanically” active 3 to 4 billion years ago. AstronomersAstronomers know this. They also know that isolated small eruptions may have continued to occur until around 3 million years ago. But today, thanks to data from missions orbiting the Red Planet, researchers at the University of Arizona (USA) report the discovery of a still active volcanic deposit in the Elysium Planitia region… 50,000 years ago!
“This may be the youngest volcanic deposit ever documented on Mars,” explains David Horvath, astronomer, in a press release from the University of Arizona. If we compressed the geological history of Mars into a single day, this would have happened at the very last second. » The eruption observed by the researchers left a smooth, dark deposit almost 13 kilometers wide, surrounding a fissure about 32 kilometers long.
Work by astronomers at the University of Arizona shows that the properties, composition and distribution of the materials correspond to the result of a pyroclastic eruption. You see, an explosive eruption of magma fueled by gases. Kind of like what you see when you open a bottle of soda after giving it a good shake.
A unique volcanic activity
Although other examples of explosive volcanism on Mars are known, astronomers emphasize the special aspect of this example. A relatively fresh, thin deposit of ash and rock. Ash and rocks that, before landing there, could have been spewed up to nearly 10 kilometers into the Red Planet's atmosphere. “It is possible that this type of deposit is more common but has been eroded or buried,” comments David Horvath.
Gigantic volcanic eruptions have changed the climate on Mars
Note that the volcanic deposit was discovered about 1,000 miles (1,600 kilometers) from the area where NASA's InSightInSight mission is currently studying seismic activity on the Red Planet. Although recent work suggests that two marsquakes recorded by the mission that were near the Cerberus Fossae could have been due to movements of deep magma.
Different dates for the same story
Another study, to be published soon, is developing models to explain this latest outbreak. The explosion could have been caused by gases already present in the magma or by its contact with Mars' permafrost. “When the ice melts, the water mixes with the magma. And it's like pouring gasoline on a fire. The water evaporates and the mixture explodes violently,” explains Pranabendu Moitra, geoscientist.
“Mars is not the dead world we imagined”
The researchers also note that the eruption occurred just 10 kilometers from the site where the most recent large impact crater on Mars was identified: Zunil. It is therefore not ruled out that the impact caused the Martian earth to shake. Enough to trigger the eruption of magma stored beneath the surface.
“All the data seems to tell the same story. Mars is not the dead world we imagined,” concludes Jeff Andrews-Hanna, planetary scientist. The discovery of this young deposit raises the possibility that volcanic activity still exists on the Red Planet and suggests that habitable conditions may have recently prevailed on Mars. The result of the interaction between the magma and the icy subsurface of the region. Be continued…