Evidence seems to be mounting for a geologically and volcanically active Mars.
A new, close study of volcanic features on the surface of the Mars has found that a lava deposit on the Elysium Planitia appears to be very recent indeed – as in, within the last 50,000 years.
On geological timescales, that’s shockingly short. And it could mean that Mars was potentially habitable even as recently, with parts of it almost like regions of volcanic activity in glacial areas like Iceland, where various sorts of extremophile bacteria thrive.
“This could also be the youngest volcanic deposit yet documented on Mars. If we were to compress Mars geologic history into one day, this might have occurred in the last moment,” said astronomer David Horvath of the Planetary Science Institute & the University of Arizona.
Mars has been filled with surprises recently, for such an apparently dry, dusty ball of rock, with several lines of evidence suggesting volcanic activity.
One is that the presence of liquid water under the surface. Mars, for all its warm coloring, may be a very cold place; a 2019 paper found that internal heating could be necessary to stay subsurface water from freezing. Then last year, another paper described how a Martian meteorite contained evidence of volcanic convection in Martian mantle.
Now, using satellite data, a team of astronomers led by Horvath has found another clue – a volcanic deposit on the Elysium Planitia, a broad, smooth plain just north of Mars’ equator.
“This feature may be a mysterious dark deposit, covering a area slightly larger than Washington DC. It’s a high thermal inertia, includes high‑calcium pyroxene-rich material, and is distributed symmetrically around a segment of the Cerberus Fossae fissure system in Elysium Planitia, a typical of aeolian, or wind-driven, deposits in region,” Horvath said.
Most volcanic features on the Martian surface are from surface lava flows, not volcanic explosions, although explosive volcanic features are never unknown. What makes the team’s discovery so interesting is that it’s on top of other, surrounding lava flows – meaning it occurred more recently.
It also appears to be relatively fresh, containing lava and ash.
“This eruption could have spewed ash as high as 10 kilometers (6.2 miles) into the Martian atmosphere but likely represents a final gasp of erupted material,” Horvath explained.
“Elysium Planitia hosts a number of the youngest volcanism on Mars, dating around 3 million years ago, so it’s not entirely unexpected. it’s possible that these kinds of deposits were more common but are eroded or buried.”
Interestingly, other hints of activity are detected within the same region. The Mars InSight lander is simply 1,600 kilometers (1,000 miles) approximately from the feature, and has detected earthquake activity in Cerberus Fossae.
Put together, the 2 pieces of evidence suggest that activity inside Mars could also be ongoing. it is vital to not over-interpret the detections, since near-surface lava so late in Mars’ life is unlikely without the presence of surface lava flows, and thus deeper magma is required to elucidate the eruption.
That’s possible, though. Earthquakes can cause eruptions of magma here on Earth, and earthquakes are detected in Cerberus Fosse; that means one potential mechanism. The feature is also not far from contemporaneous impact crater, called Zunil. That impact could even have triggered volcanic activity.
However the eruption was triggered, the detection raises the intriguing prospect – albeit still a slim prospect – of relatively recent life on Mars, almost like those found at hydrothermal vents on Earth, where extremely cold conditions meet boiling hot temp. Microbial life thrives at these locations, relying not on photosynthesis but chemical reactions for survival.
“The interaction of ascending magma and therefore the icy substrate of this region could have provided favorable conditions for microbial life fairly recently and raises possibility of extant-life in this region,” Horvath said.
This could help plan out future Mars missions by providing a location where evidence of life could be found.
The research has been published in Icarus.