Recent volcanism on Mars shows the planet is more active than previously thought

A vast, flat and “featureless” plain on Mars has surprised researchers by revealing a much more turbulent geological history than expected, according to a study by researchers at the University of Arizona. About 1 million years ago, massive amounts of lava erupted from numerous fissures, covering an area nearly the size of Alaska and causing massive floods as it interacted with water above and below the surface, creating deep channels.

Due to its lack of plate tectonics (fragments of crust that constantly change the shape of the Earth’s surface), Mars has long been considered a “dead” planet with little going on geologically. However, recent discoveries have led researchers to question this concept. Just last year, a team of planetary scientists, also from the University of Arizona, presented evidence of a giant mantle plume beneath the Elysium Planitia region that had caused intense volcanic and seismic activity in the relatively recent past.

In the latest study, a team led by Joanna Voigt and Christopher Hamilton of the University of Arizona Lunar Planetary Laboratory combined spacecraft images and ground-based radar measurements to reconstruct each lava flow at Planitia Elysium in three-dimensional detail. A major study identified and documented more than 40 volcanic events; One of the largest flows filled the so-called Athabasca Valley with nearly 1,000 cubic miles of basalt.

“Planitia Elysium is the youngest volcanic region on the planet, and studying it helps us better understand the past and recent hydrological and volcanic history of Mars,” the authors write in their paper. Although no volcanic activity has yet been observed on Mars, “Elysium Planitia was much more volcanically active than previously thought and may even be volcanically alive today,” said Voigt, first author of the study published in the Journal. Geophysical Research: Planets. Multiple earthquakes recorded on Mars by NASA’s InSight lander between 2018 and 2022 proved that there are no dead people beneath the surface of the red planet.

“Our study provides the most complete description of recent geologic volcanism on a planet other than Earth,” said Hamilton, the LPL associate professor. “This is the best estimate of young volcanic activity on Mars for about the last 120 million years, corresponding to the period when dinosaurs were at their peak on Earth by now.”

According to the authors, these findings contain clues for research into whether life might have existed at some point in Mars’ history. Elysium Planitia experienced many major floods, and there is evidence that erupting lava interacted with water or ice to shape the landscape in dramatic ways. On the planet Elysium, Voigt and his co-authors found abundant evidence of steam explosions, interactions that are of great interest to astrobiologists because they may have created a hydrothermal environment conducive to microbial life.

The team combined images from the Context camera aboard NASA’s Reconnaissance Orbiter (MRO) with even higher resolution images from the UArizona-led HiRISE MRO camera in selected regions. To obtain the topographic information, they used data records from the Mars Orbiter laser altimeter on another NASA spacecraft, the Mars Global Surveyor. This data was then combined with subsurface radar measurements taken by NASA’s Shallow Radar, or SHARAD, probe.

“With SHARAD, we were able to look 140 meters (460 feet) below the surface,” said Voigt, who completed the research while pursuing his doctorate at the University of Arizona. He is currently a postdoctoral researcher at the Jet Propulsion Laboratory at the California Institute of Technology (JPL) in Pasadena, California.

“Combining the datasets allowed us to reconstruct a three-dimensional view of the study area, including what the topography was like before lava erupted from numerous fissures and filled basins and channels previously cut off by flowing water,” Voigt said. he added.

The interior of Mars is believed to be very different from that of Earth, and detailed reconstructions of its geological features are giving scientists an insight into the processes that shaped it in the past. According to Hamilton, the connection between volcanoes and the structure of the Martian crust is key to understanding the planet’s paleoenvironmental conditions. In addition to water contained in magma being released into the atmosphere and then freezing at the surface, a volcanic eruption can cause a catastrophic release of groundwater to the surface.

“When there is a crack in the crust of Mars, water can flow to the surface,” Hamilton said. “Due to low atmospheric pressure, this water will likely literally boil away. However, if enough water is released during this period, a massive flood could occur that would overwhelm the landscape and shatter these huge details we see.”

Understanding how water moved on Mars in the past and where it is today is the “holy grail,” according to the authors. Because it is much easier to land in the equatorial regions where the planet Elysium is located than in the planet’s higher latitudes, understanding the existence of water and its release mechanisms will inform future human missions that will critically depend on this resource.

“Elysium Planitia is an ideal place to try to understand the connection between what we see on the surface and the internal dynamics that occur through volcanic eruptions,” Voigt said. “I paid close attention to the details on the surface of the lava to unravel the various eruptive events and reconstruct the entire history of these geological formations.”

The team plans to continue leveraging large, complex data sets produced by a variety of imaging techniques to combine highly detailed 3D representations of the Martian surface and what lies beneath it with time sequences of events in other volcanically active regions.

Voigt likens lava flow surfaces to “open books that contain a wealth of information about how they formed, if you know how to read them.”

“I think that areas like Elysium Planitia, which used to be considered vague and boring, hold a lot of secrets, and you want to read them,” he said.