Giant Mantle Plume Reveals Mars is More Active Than Previously Thought

On Earth, shifting tectonic plates reshuffle the planet’s surface and make for a dynamic interior, so the lack of such processes on Mars led several to think of it as a dead planet where not much occurred in the past 3 billion years.

In the present problem of Nature Astronomy, researchers from the College of Arizona difficulty current views of Martian geodynamic advancement with a report on the discovery of an active mantle plume pressing the surface area upward and causing earthquakes and volcanic eruptions. The finding indicates that the planet’s deceptively quiet surface area might hide a more tumultuous interior than formerly thought.

An active mantle plume on Mars

“Our study presents several lines of evidence that expose the existence of a huge active mantle plume on present-day Mars,” stated Adrien Broquet, a postdoctoral research study associate in the UArizona Lunar and Planetary Lab and co-author of the research with Jeff Andrews-Hanna, an associate professor of planetary science at the LPL.

Mantle plumes are big blobs of warm and also buoyant rock that rise from deep inside a planet and press through its intermediate layer– the mantle– to reach the base of its crust, causing earthquakes, faulting, and volcanic eruptions. For instance, the island chain of Hawaii formed as the Pacific plate slowly drifted over a mantle plume.

“We have a strong proof for mantle plumes being active on Earth and also Venus, but this isn´t expected on a tiny and supposedly cold world like Mars,” Andrews-Hanna stated. “Mars was most active three to four billion years back, and the prevailing view is that the planet is essentially dead today.”

“An incredible quantity of volcanic activity early in the planet’s history built the highest volcanoes in the solar system and also blanketed most of the northern hemisphere in volcanic deposits,” Broquet stated. “What little activity has occurred in recent background is generally attributed to passive processes on a cooling planet.”

Studying Elysium Planitia

The scientists were drawn to a surprising amount of activity in an otherwise nondescript area of Mars called Elysium Planitia, a plain within Mars’ north lowlands close to the equator. Unlike other volcanic regions on Mars, which have not seen major activity for billions of years, Elysium Planitia experienced huge eruptions over the past 200 million years.

“Previous work by our team discovered evidence in Elysium Planitia for the youngest volcanic eruption known on Mars,” Andrews-Hanna stated. “It created a tiny explosion of volcanic ash about 53,000 years back, which in geologic time is basically yesterday.”

Volcanism at Elysium Planitia comes from the Cerberus Fossae, a set of young fissures that stretch for greater than 800 miles across the Martian surface area. Recently, NASA’s InSight group found that almost all Martian quakes, or marsquakes, emanate from this one area. Although this young volcanic and tectonic activity had been documented, the underlying cause remained unknown.

On Earth, volcanism and earthquakes have the tendency to be associated with either mantle plumes or plate tectonics, the international cycle of drifting continents that continually recycles the crust.

Mantle Plumes

“We know that Mars doesn´t have plate tectonics, so we investigated whether the activity we observe in the Cerberus Fossae area could be the result of a mantle plume,” Broquet stated.

Mantle plumes, which could be viewed as analogous to hot blobs of wax rising in lava lamps. Give away their existence on Earth through a classical sequence of events. Warm plume material presses against the surface, uplifting and stretching the crust. Molten rock from the plume after that erupts as flood basalts that develop vast volcanic plains.

When the team examined the features of Elysium Planitia, they discovered evidence of the same sequence of events on Mars. The surface has been uplifted by greater than a mile, making it one of the greatest regions in Mars’ vast northern lowlands. Evaluations of refined variations in the gravity field suggested that this uplift is supported from deep within the planet, consistent with the existence of a mantle plume.

The Impact Craters

Other measurements revealed that the floor of impact craters is tilted in the plume direction, further supporting the concept that something pressed the surface up after the craters were created. Lastly, when scientists applied a tectonic design to the location, they found that the existence of a giant plume 2,500 miles wide was the only way to describe the extension responsible for creating the Cerberus Fossae.

“In terms of what you expect to observe with an active mantle plume, Elysium Planitia is checking all the right boxes,” Broquet stated, adding that the finding poses a difficulty for models utilized by planetary scientists to study the thermal evolution of planets. “This mantle plume has impacted a location of Mars approximately equivalent to that of the continental United States. Future research studies will need to find a way to account for a very huge mantle plume that was not expected to be there.

“We utilized to think that InSight landed in one of the most geologically boring areas on Mars– a nice flat surface that should be approximately representative of the planet’s lowlands,” Broquet added. “Instead, our research study shows that InSight landed right on top of an active plume head.”

The existence of an active plume will impact interpretations of the seismic information recorded by InSight, which should now take into consideration the fact that this region is far from typical for Mars.

” Having an active mantle plume on Mars today is a paradigm shift for our understanding of the planet’s geologic advancement,” Broquet stated, “similar to when analyses of seismic measurements recorded during the Apollo age demonstrated the moon’s core to be molten.”

Implications for life on Mars

Their findings could additionally have implications for life on Mars, the authors state. The examined region experienced floods of liquid water in its current geologic past, though the cause has remained a secret. The same warm from the plume that is fueling continuous volcanic and seismic activity might likewise melt ice to make the floods– and drive chemical reactions that would sustain life deep underground.

” Microbes on Earth flourish in atmospheres like this, which could be true on Mars, as well,” Andrews-Hanna stated, adding that the discovery goes beyond describing the enigmatic seismic activity and resurgence in volcanic activity. “Understanding that there is an active giant mantle plume underneath the Martian surface raises essential questions regarding how the planet has advanced over time. “We are convinced that the future has more surprises in store.”

Read the original article on SCIENCE DAILY.

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