This image shows digital elevation data overlaid on daytime thermal
infrared images of Eden Patera, the type example of an ancient
supervolcano on Mars. Red colors are relatively high and purple-gray
colors are low. Image released Oct. 2, 2013. (NASA/JPL/GSFC/Arizona State University)
In a report
that appeared in the journal Nature this week, scientists say they have
discovered a supervolcano on Mars for the first time. The scientists
determined that a vast circular basin on the face of the Red Planet is
actually the remains of an ancient supervolcano eruption. To reach this
conclusion, the team used images and topograhic data from NASA’s Mars Odyssey, Mars Global Surveyor and Mars Reconnaissance Orbiter spacecraft.
“On Mars, young volcanoes have a very distinctive appearance that allows us to identify them,” stated Joseph R. Michalski, a Senior Scientist at the Planetary Science Institute, who led the study. “The long-standing question has been what ancient volcanoes on Mars look like. Perhaps they look like this one.”
The researchers said a large body of magma loaded with dissolved gas
rose through a thin crust to the surface rapidly, like a bottle of soda
that has been shaken. This supervolcano would have ejected its contents
far and wide, spilling ash and material across vast swaths of the Red
Planet.
“This highly explosive type of eruption is a game-changer, spewing
many times more ash and other material than typical, younger Martian
volcanoes,” said Jacob E. Bleacher of NASA Goddard Space Flight Center,
who co-authored the paper. “During these types of eruptions on Earth,
the debris may spread so far through the atmosphere and remain so long
that it alters the global temperature for years.”
When the supervolcano expelled all its material from the eruption, it
caused all the ground around it to sink like a balloon deprived of its
air.
The supervolcano is located in the Arabia Terra region of Mars, which
is a battered terrain loaded with impact craters. When Michalski
examined this particularly basin more closely, he noticed that it lacked
the raised rim that an impact crater typically has. He was also unable to find a blanket of ejecta, the melted rock that splashes outside the crater when an object hits.
After noting this, Michalski contacted Bleacher, who identified
features at Eden Patera that usually indicate volcanic activity. The
scientists found that the outside of the basin is ringed by the kinds of
faults and valleys that occur when the ground collapses because of
activity below the surface. They also found a few more basins nearby
that are volcano candidates.
“If just a handful of volcanoes like these were once active, they
could have had a major impact on the evolution of Mars,” Bleacher said
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