Washington [US] DECEMBER 6 (ANI): On Earth, moving tectonic plates alter the planet’s surface and create a dynamic internal structure, so the absence of such processes on Mars leads many to consider it a dead planet, since not much happens on Earth. last 3 billion years.
In the new issue of Nature Astronomy, University of Arizona scientists challenge current views on the geodynamic evolution of Mars by reporting the discovery of active mantle plumes that push the surface up and cause earthquakes and volcanic eruptions. The findings suggest that the planet’s seemingly deserted surface may be hiding a much more turbulent interior than previously thought.
“Our study provides a wealth of evidence suggesting the existence of active giant mantle plumes on Mars today,” said Adrien Broquet, postdoctoral researcher at the UArizona Lunar and Planetary Laboratory and co-author of the study with Jeff Andrews. Hanna, a professor of planetary science at the LPL.
The mantle plume is a large mass of hot, muddy rock that rises from deep within the planet and pushes through the middle layer – the mantle – to reach the bottom of the crust, causing earthquakes, faults and volcanic eruptions. The Hawaiian island chain, for example, was formed as the Pacific Plate moved slowly along the mantle.
“We have strong evidence of mantle plume activity on Earth and Venus, but this would be unexpected on a small and possibly cold world like Mars,” Andrews-Hanna said. “Mars was most active 3 to 4 billion years ago, and the prevailing view today is that the planet is virtually dead.”
“A tremendous amount of volcanic activity early in the planet’s history built the tallest volcanoes in the solar system and blanketed much of the northern hemisphere in volcanic deposits,” Broquet said. “Minor activities that have occurred in recent history are usually associated with passive processes on cold planets.”
The researchers were drawn to a surprising amount of activity in an inconspicuous region of Mars called Elysium Planitia, a plain in Mars’ northern lowlands near the equator. Unlike other volcanic regions on Mars, which have seen little activity for billions of years, Elysium Planitia has experienced major eruptions over the past 200 million years.
“Previous work by our group has found evidence in Elysium Planitia of the most recent known volcanic eruptions on Mars,” said Andrews-Hanna. “It produced a small eruption of volcanic ash about 53,000 years ago, most of which was geological yesterday.”
The volcanoes on Elysium Planitia originate from the Cerberus Fossae, a collection of tiny fissures that stretch more than 800 miles across the Martian surface. Recently, NASA’s InSight team discovered that almost all Martian earthquakes or earthquakes originate in this region. While this juvenile volcanic and tectonic activity has been documented, the underlying causes are still unknown.
On Earth, volcanoes and earthquakes tend to be associated with mantle plumes or plate tectonics, the global cycle of continents constantly recycling the earth’s crust.
“We know Mars doesn’t have plate tectonics, so we tested whether the activity we saw in the Cerberus Fossae region was caused by mantle plumes,” Broquet said.
a mantle feather, which is analogous to a plume of hot wax rising in a lava lamp. they have given up their presence on Earth through a classic series of events. The warm fleece material pushes against the surface, lifting and stretching the crust. The molten rock then erupts from the column in the form of flood basalts creating extensive volcanic plains.
When the team studied the features of Elysium Planitia, they found evidence of a similar series of events on Mars. Its surface has been raised over a mile, making it one of the highest on Mars’ vast northern plains. Analysis of subtle variations in the gravitational field shows that this uplift is supported by the planet’s depth, consistent with the presence of a mantle plume.
Further measurements showed that the floor of the impact crater sloped toward the plume, supporting the idea that something lifted onto the surface after the crater formed. Finally, when the researchers applied tectonic models to the region, they found that the presence of a giant plume, 2,500 miles wide, was the only way to explain the expansion responsible for the formation of Cerberus Fossae.
“In terms of what you would expect to see with the mantle plume active, Elysium Planitia ticks all the right boxes,” Broquet said, adding that the discovery challenges the models used by planetary scientists to study planetary thermal evolution. . “This mantle plume affects an area of Mars about the size of the continental United States. Future studies should find a way to explain the huge mantle plume that is not thought to be present.
“We thought InSight had landed in one of the more geologically boring areas of Mars, a nice flat surface that roughly corresponds to the planet’s lowlands,” Broquet added. “In contrast, our research shows that InSight landed directly on an active blob.”
The presence of an active plume will affect the interpretation of seismic data recorded by InSight, which now has to take into account that this region is anything but normal for Mars.
“The presence of active mantle plumes on Mars today is a paradigm shift in our understanding of the planet’s geological evolution, similar to what happened when analysis of seismographs recorded during the Apollo era showed that the moon’s core is liquid.” “Broquet said.
The authors say their findings could also have implications for life on Mars. The study area has experienced liquid water flooding in its geological past, although the cause remains a mystery. The same plume heat that fuels ongoing volcanic and seismic activity can also melt ice that causes flooding and triggers chemical reactions that can sustain life underground.
“Microbes on Earth thrive in this kind of environment, and that’s also true on Mars,” Andrews Hanna said, adding that the finding goes beyond explaining the puzzling seismic activity and increased volcanic activity. “Knowing that there are giant plumes active beneath the Martian surface raises important questions about how the planet has evolved over time.” We are certain that the future will hold even more surprises. (ANI)
