We may be a long way from putting humans on Mars, but that hasn’t stopped scientists from placing sophisticated equipment on the Martian surface to find evidence of life now or once on the Red Planet … and one of those machines just detected a rumble that might mean there is something hot and molten below the surface of what has long been thought to be a cold, hard orb. On Earth, ‘hot and molten’ usually means lava when it is shooting out of a volcano like the Mauna Loa which is currently erupting, or magma when it is still trapped underneath the surface. Believe it or not, it may now mean the same thing on Mars – data from NASA’s InSight rover’s “mole” is showing an active mantle plume, which on Earth means a giant column of hot molten rock which drives volcanic activity and earthquakes by pushing hot magma up from the mantle to the planetary crust. This means Mars may have active volcanic activity – the kind that melts ice into water and sparks chemicals into life forms. Will a mechanical probe find life on Mars before humans arrive?
“Although the majority of volcanic and tectonic activity on Mars occurred during the first 1.5 billion years of its geologic history, recent volcanism, tectonism and active seismicity in Elysium Planitia reveal ongoing activity.”
As a new study published this week in Nature Astronomy reminds us, there was once volcanic activity on Mars, but it was 4 billion years ago. That has been confirmed by various satellites, rovers and landers which found tracks of ancient lava flows on the planet’s surface. C-authors Adrien Broquet, a postdoctoral research associate in the University of Arizona Lunar and Planetary Laboratory (LPL), and Jeff Andrews-Hanna, an associate professor of planetary science at the LPL, were intrigued by new data from NASA’s InSIght (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander. Since it touched down in 2018, InSight has been measuring marsquakes with its Seismic Experiment for Interior Structure (SEIS) instrument and recording underground heat with its Heat Flow and Physical Properties Package (HP3), which includes a probe nicknamed "the mole", which was designed to burrow 16 feet below the surface but only got to about 1.1 feet. Nonetheless, the equipment picked up a surprising amount of marsquakes and heat and virtually all of it was emanating from a region called Elysium Planitia, a plain close to the equator. According to the press release:
"Previous work by our group found evidence in Elysium Planitia for the youngest volcanic eruption known on Mars. It created a small explosion of volcanic ash around 53,000 years ago, which in geologic time is essentially yesterday."
While the rest of the planet hasn’t had any shaking going on in billions of years, Elysium Planitia has had large eruptions over the past 200 million years that continue to today -- as of May 2022, Insight had recorded 1,313 marsquakes but scientists were unable to determine what was causing them. Broquet and his team knew Mars does not have plate tectonics like Earth, so the only other cause of the marquakes would be a mantle plume. Think of them as blobs of molten magma bubbling to the surface where they either nestle under the crust, warming the area above them, or burst through fissures to cause quakes, volcanoes and lava flows. The data showed that Elysium Planitia had been lifted up a mile high by something under the Martian surface. When the data was fed into a tectonic model, it showed the presence of a plume … and it was a monster.
"This mantle plume has affected an area of Mars roughly equivalent to that of the continental United States. Future studies will have to find a way to account for a very large mantle plume that wasn't expected to be there.”
What was thought to be a dead spot when it was chosen as the landing spot for InSight turned out to be a 2,500 miles wide cap on a massive magma plume. As the study exclaims, this is a big deal.
“Our results demonstrate that the interior of Mars is geodynamically active today, and imply that volcanism has been driven by mantle plumes from the formation of the Hesperian volcanic provinces and Tharsis in the past to Elysium Planitia today.”
There is volcanic activity on Mars today. Broquet calls this “a paradigm shift for our understanding of the planet’s geologic evolution." It means Mars is not a cold, dead orb but a warm, active one … at least under the surface. That, as we now know, is where Marian ice is hiding. The heart of the magma means that ice could be water. And that means this could be a paradigm shift in the search for life on Mars as well.
"Microbes on Earth flourish in environments like this, and that could be true on Mars, as well. Knowing that there is an active giant mantle plume underneath the Martian surface raises important questions regarding how the planet has evolved over time. We're convinced that the future has more surprises in store."
More surprise like … microbes living deep beneath the Martian surface? How about just 30 feet below it? Dr. Amy J. Williams, an assistant professor of geology at the University of Florida and not part of the study, thinks they could have been there in the not too distant past and perhaps are still there in a dormant state. She tells National Geographic:
“I wouldn’t put it past the Martian microbe to beat the odds and survive for an extended period. Whether it’s still there today, I can’t hazard a guess. But as an astrobiologist, my hope is that it is, and that maybe that knowledge can help us have a deeper appreciation for our place in the universe.”
Until now, Earth and Venus were the only planets in the Solar System known to have active mantle plumes … coincidentally, these were also the only planets to either have life or have strong signs of the possibility of life. We now have a third.