Olympus Mons is the latest hotspot in the hunt for habitable zones on Mars.
The Martian volcano is about three times the height of Mount Everest, but it’s the small details that matter to Rice University professors Patrick McGovern and Julia Morgan. After studying computer models of Olympus Mons’ formation, McGovern and Morgan are proposing that pockets of ancient water could still be trapped under the mountain. Their research is published in February’s issue of the journal Geology.
Olympus Mons is tall, standing almost 15 miles (24 km) high, and slopes gently from the foothills to the caldera, a distance of more than 150 miles (241 km). That shallow slope is a clue to what lies beneath, say the researchers. They suspect if they were able to stand on the northwest side of Olympus Mons and start digging, they’d eventually find clay sediment deposited there billions of years ago, before the mountain was even a molehill.
In modeling the formation of Olympus Mons with an algorithm known as particle dynamics simulation, McGovern and Morgan determined that only the presence of ancient clay sediments can account for the volcano’s asymmetric shape. The presence of sediment indicates water was or is involved.
The European Space Agency’s Mars Express spacecraft has in recent years found abundant evidence of clay on Mars. This supports a previous theory that where Olympus Mons now stands, a layer of sediment once rested that may have been hundreds of meters thick.
Morgan and McGovern show in their computer models that volcanic material was able to spread to Olympus-sized proportions because of the clay’s friction-reducing effect, a phenomenon also seen at volcanoes in Hawaii.
But fluids embedded in an impermeable, pressurized layer of clay sediment would allow the kind of slipping motion that would account for Olympus Mons’ spread-out northeast flank – and they may still be there. And because NASA’s Phoenix lander found ice underneath the Martian surface last year, Morgan and McGovern believe it’s reasonable to suspect water could be trapped in the sediment underneath the mountain.
“This deep reservoir, warmed by geothermal gradients and magmatic heat and protected from adverse surface conditions, would be a favored environment for the development and maintenance of thermophilic organisms,” they wrote. On Earth, such primal life forms exist along deep geothermal vents on the ocean floor.
Finding a source of heat will be a challenge, Morgan and McGovern admit. “We’d love to have the answer to that question,” said McGovern. He noted that evidence of methane on Mars is considered by some to be another marker for life.
LEAD IMAGE CAPTION: Rice University professors Patrick McGovern and Julia Morgan are proposing that pockets of water could be trapped under Olympus Mons on Mars — and could support life. Credit: Rice University