Arsia Mons is one of the largest volcanoes on Mars, and may have been actively producing lava flows as recently as 50 million years ago. Credit: NASA/JPL/USGS
One of Mars’s biggest volcanoes erupted for the last time just as dinosaurs on Earth were becoming extinct, NASA has found.
Arsia Mons is located just south of the Martian equator, part of a trio of volcanoes known collectively as Tharsis Montes.
"We estimate that the peak activity for the volcanic field at the summit of Arsia Mons probably occurred approximately 150 million years ago - the late Jurassic period on Earth - and then died out around the same time as Earth's dinosaurs," says Jacob Richardson, a postdoctoral researcher at NASA's Goddard Space Flight Center.
"It's possible, though, that the last volcanic vent or two might have been active in the past 50 million years, which is very recent in geological terms."
This “recent” activity is thought to have occurred in the caldera; a depression at the top of the volcano where 29 vents have been identified.
This caldera measures about 110km across and was imaged by NASA’s Mars Reconnaissance Orbiter.
The team behind the study were able to use these images to map the boundaries of the lava flows from each of the 29 volcanic vents.
They also counted the number of craters of at least 100m in diameter to measure the ages of the flows.
Using this information, they were able to determine that the earliest flows from the volcano date back about 200 million years, while the youngest occurred 10 - 90 million years ago, but most likely 50 million years ago.
The team also concluded that about 150 million years ago the vents in Arsia Mons’ caldera were producing one to eight cubic kilometres of magma every million years.
"A major goal of the Mars volcanology community is to understand the anatomy and lifecycle of the planet's volcanoes,” says Jacob Bleacher, a planetary geologist at Goddard and a co-author of the study.
“Mars's volcanoes show evidence for activity over a larger time span than those on Earth, but their histories of magma production might be quite different.
This study gives us another clue about how activity at Arsia Mons tailed off and the huge volcano became quiet."