Using data from satellites orbiting Mars, a study has found evidence of an eruption 50,000 years ago in an area called Elysium Planitia believed to be the youngest known volcanic eruption on Mars.
Like Earth, Mars is a differentiated body with a crust, mantle and core. On Earth, large blobs of hot material rise upwards in the silicate mantle, driving plate tectonics and fueling interplate volcanism over so-called hotspots, as in the case of Hawaii. Unlike Earth, Mars is not thought to have experienced significant plate tectonics. But Mars exhibits hotspot type volcanism which is similar to interplate volcanism.
The Hawaiian style of low-viscosity effusive volcanism dominates Mars and has resulted in the development of massive shield volcanoes and individual flows over 1,000 km long. But because Mars is significantly smaller than Earth, losing its internal heat much faster, most researchers believe the planet is no longer geologically active.
Most volcanism on Mars occurred between 3 and 4 billion years ago, with smaller eruptions in isolated locations continuing perhaps as recently as 3 million years ago.
But the new study describes a geological feature with properties similar to volcanic materials found on Earth, and the absence of craters suggests a very young age between 50,000 and 210,000 years old.
“This feature is a mysterious dark deposit, covering an area slightly larger than Washington, D.C. It has high thermal inertia, comprises high-calcium pyroxene-rich material, and is symmetrically distributed around a segment of the fissure system of Cerberus Fossae in Elysium Planitia, atypical of aeolian – or wind-driven – deposits in the region. This feature is similar to dark spots on the Moon and Mercury suggested to be explosive volcanic eruptions,” explains the lead author of the paper. study, David Horvath. “This may be the youngest volcanic deposit ever documented on Mars. If we were to compress the geological history of Mars into a single day, it would have happened in the very last second.”
The majority of volcanism in the Elysium Planitia region and elsewhere on Mars consists of lava flowing on the surface, although there are many examples of explosive volcanism on Mars. However, this repository appears to be different. “This feature overlies the surrounding lava flows and appears to be a relatively fresh deposit of ash and rock, representing a different style and timing of eruption from previously identified pyroclastic features,” Horvath said. “This eruption could have spewed ash up to 10 kilometers into the Martian atmosphere, but likely represents a last gasp of erupting material. Elysium Planitia is home to some of Mars’ youngest volcanoes, dating to around 3 million ago. years, so it’s not entirely unexpected. It’s possible that these types of deposits were more common but were eroded or buried.”
The site of the recent eruption is about 1,000 miles (1,600 km) from NASA’s InSight lander, which has been studying tectonic activity on Mars since 2018. Two Marsquakes have been located in the region around the Cerberus Fossae and recent work have suggested the possibility that these could be due to the movement of magma at depth.
“The young age of this deposit absolutely raises the possibility that there could still be volcanic activity on Mars and it is intriguing that the recent Mars tremors detected by the InSight mission are from the Cerberus Fossae,” Horvath said. “However, maintaining magma near the surface of Mars this late in Mars’ history without associated lava flows would be difficult and therefore a deeper magma source would likely be required to create this eruption.”
A volcanic deposit like this also raises the possibility of habitable conditions near the surface of Mars in recent history, Horvath says. “The interaction of the rising magma and the icy substrate of this region could have provided favorable conditions for microbial life quite recently and raises the possibility of extant life in this region.”