NASA has found perhaps the youngest site of major volcanic activity on Mars. Based on satellite observations, our celestial neighbor’s Arsia Mons volcano was still blowing its top 16 million years after Earth’s gigantic groundwalking dinosaurs bit the bullet.
“We estimate that the peak activity for the volcanic field at the summit of Arsia Mons probably occurred approximately 150 million years ago,” lead author Jacob Richardson, a postdoctoral researcher at NASA’s Goddard Space Flight Center, said in a statement. “It’s possible that the last volcanic vent or two might have been active in the past 50 million years, which is very recent in geological terms.”
Using high-resolution imagery from NASA’s Mars Reconnaissance Orbiter, the team dated the lava flows from the volcano's 29 nested vents by looking at how many craters they contained. Generally speaking, younger lava flows contain less craters, whereas older ones look more like Swiss cheese.
Their satellite mapping revealed that Arsia Mons was born around 200 million years ago, and was likely to be one of the last active volcanoes on Mars.
It also erupted a lot less frequently compared to our own towering mountains of fire. The 110-kilometer-long (68-mile-long) cauldron-like central crater manufactured a fresh, lava-spewing vent once every 1 to 3 million years, compared to one every 100,000 years in comparable regions on Earth.
A topographic map of Arsia Mons, which shows it's around 20 kilometers (12 miles) high - more than twice that of Everest. Martin Pauer/Wikimedia Commons; CC BY 3.0
The study, published in Earth and Planetary Science Letters, adds credence to the idea that the volcanism on Mars was fairly different from that of Earth’s.
Due to the failure of plate tectonics, and thanks to the different geological makeup of the planet’s innards, you don’t get complex magma chambers producing mountain-like stratovolcanoes (see: Mount St. Helens).
Instead, you had upwelling plumes of superheated mantle material that generated vast, flat shield volcanoes (see: Hawaii’s Kilauea). Every now and then, magma also erupted into an ice field, which caused sudden and violent explosive events that left the planet covered in depression craters reminiscent of micro-nuclear weapon blast scars.
Geologically speaking, Mars is pretty dead these days. There hasn’t been a significant volcanic eruption on the Red Planet for tens of millions of years, with the famously massive shield volcano, Olympus Mons, being one of the last firelights to go out.
At some point, the thermal fuel source hiding beneath the Martian crust was no longer sufficient to produce volcanic activity – so, in recent times, the Red Planet has enviously watched Earth’s firework displays while lacking any of its own.
Don’t judge Mars too harshly though. Several billion years back, a truly epic volcanic eruption ejected much of the planet’s mantle onto the surface. This caused Mars to tip over by 20° – which would be like moving Paris to the North Pole.