Volcanic Activity on Mars Upends Red Planet Assumptions

For decades, planetary scientists thought Mars was dead.

Geologically yes. A planet smaller than Earth would have cooled faster than our planet after it formed. There was considerable volcanic activity for some time. However, as one might think, the gradual decline in internal temperature also reduced the planet’s ability to generate large-scale geological activity, such as giant volcanoes and quakes.

But recent discoveries refute that belief.Mars just happens to be In many cases Death; Scientists have discovered that large areas of Mars are prone to earthquakes and even mild volcanic activity in recent geological times. Something Brewed under water. But what?

Examining data from several robotic Mars missions, a team of planetary scientists found that huge towers of hot material moving upward in the planet’s mantle are pushing the crust from below, causing cracks in the surface. I came to the surprising conclusion that it produces crustal activity. This phenomenon, called the mantle plume, is a relatively new feature inside Mars and may have analogues on or below Earth. It could even affect existing life on Mars. More precisely, Under That.work was published in natural astronomy.

Mars was once a planet with intense volcanic activity. The surface is dotted with these ancient mounds, including one called the Olympus Mons. This monster is over 600 kilometers in diameter, roughly the length of the state of Colorado. Its height is 21 kilometers above the Earth’s average surface elevation, about 2.5 times that of Mount Everest. Other volcanoes on Mars are smaller, but still huge and horribly old.

Large-scale volcanic activity began less than a billion years after the formation of Mars and continued for about a billion years thereafter. After that, volcanic activity ceased worldwide. There is evidence of lava flows at Mount Olympus dating only a few million years ago, but these are small events and may be sporadic. Gone are the days when the was built. For comparison, most active volcanoes on Earth are less than a million years old.

Until recently, scientists thought the story of volcanic activity on Mars was over. However, a spacecraft orbiting Mars recently captured high-resolution images showing that the final chapter has yet to be written.In an area called Cerberus Fossae, there are numerous cracks in the surface (groove One such feature is a dark streak of material that runs along it for tens of kilometers. Measurements from orbit show that the material contains pyroxene, a mineral associated with explosive volcanic events called pyroclastic flows. Amazingly, these spills may have occurred just tens of thousands of years ago.that is these days, And it shows the activity going on under the surface.

Additionally, in 2018, NASA’s InSight lander landed on Mars in a region called Elysium Planitia, about 1,600 kilometers from Cerberus Fosse. InSight, a mission to help measure what is happening beneath the surface of Mars, has seismometers that have detected hundreds of small earthquakes over the past few years, some of moderate to moderate energy. It was moderate. The overwhelming majority of them seem to have come from the direction of Cerberus Fossae. Again, this indicates that Mars’ mantle may not be completely dead yet.

recently natural astronomy In their research, scientists focused on this region of Mars. Many of the planet’s surfaces show compressive features, such as wrinkle ridges, that form when the planet’s surface contracts as it cools. However, the Elysium Plain has bulges on its surface. Evidence of expansion, stretching the crust as the local area expands. The fissures that make up Cerberus Fossae are fissures where the crust separated from this extension. Scientists also note that the floors of impact craters formed millions of years ago tilt away from the center of the bulge. This is to be expected if the surface were formed before being pushed up. Taken together, these findings indicate that whatever caused the bump was relatively young.

All this evidence is consistent with a mantle plume. If you’ve ever seen boiling water or a hot air balloon in flight, the basic idea of ​​a plume is familiar. In fluids, hot matter rises and cold matter sinks, a process called convection. The core of the planet is hot, and the mantle above it is rather cold, causing heated material at the bottom to rise.

The curveball here is that much of Mars’ (and Earth’s) mantle is actually solid. It is a misconception that it is a liquid. But convection also works in solids. The silicate material that makes up most of the mantle is crystalline and may have flaws and fissures in the crystal pattern. Under immense pressure deep underground, atoms from the material below can fill these cracks in the structure in a process called dislocation creep. It can rise and flow essentially. This is a very slow process. The Earth’s mantle flows at a velocity of about 2 cm per year. This is half the speed at which nails grow.

It is not known exactly how mantle plumes form. At the bottom of the mantle above the core, hotter-than-average spots can create regions of stronger convection, where material flows in more constrained columns. It rises to the surface over a period of time and near the crust, the pressure is much lower, and solid matter can liquefy. causes extensions such as

This scenario explains essentially all anomalies of Cerberus Fossae, including upheavals, fissures, volcanic eruptions, and earthquakes. Measurements of Mars’ gravitational field even show that the field is slightly weaker under Cerberus Fossae, consistent with a low-density mantle pushed up beneath the crust. This indicates that the ridge is supported very deep underground.

Scientists have used computer models to simulate the geophysics of Mars and found that plumes that are about 95 to 285 degrees Celsius warmer and slightly less dense than the surrounding mantle, which lies almost directly beneath the fossa, do well. discovered. It forms a cap that stretches for about 2,500 kilometers and pushes up the crust by about 1 kilometer, also consistent with Cerberus Fosse. It is also a young feature. Activity in and around Cerberus Fossae appears to have begun about 350 million years ago, long after all other large-scale engines on Earth had effectively stopped.

The plume model agrees very well with the observational data, but scientists admit there are other possible explanations. For example, a slightly less dense mass of mantle material may lie beneath the region. This accounts for gravity measurements, but not for prominence or anything else.

If our hypothesis is correct, this is important news. For one thing, many of the conclusions scientists have drawn about the interior of Mars based on InSight’s seismic measurements assume that Elysium Planitia is boring and just another part of Mars. When it’s at the top of a tremendous plume of hot, low-density material, it changes how you interpret InSight’s data.

It’s a bit of an exaggeration for now, but plumes can also affect life. Scientists believe that subsurface water on Mars is in the form of ice, but the warm mantle her plumes can heat pockets of water enough to make them liquid. On Earth, life needs liquid water, so it might not be silly to think that biology could exist deep on Mars’ surface.

In that case, Mars isn’t completely dead, either geologically or in the more general biological sense. You can see that the stimulus remains.

This is an opinion and analysis article and the views expressed by the author or authors are not necessarily Scientific American.

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