Researchers at the European Space Agency believe a giant impact crater spotted on Mars may hold the remains of an ancient supervolcano.
The revealing images were taken by the high-resolution stereo camera on ESA's Mars Express on Nov. 26, 2014, and represent the Siloe Patera feature in the Arabia Terra region.
Researchers have suggested some of the craters visible in the images are actually calderas, which are the collapsed centers of volcanoes. These calderas would not be the remains of just any volcanoes, but rather massive supervolcanoes that are created when magma build up below the surface, creating immense pressure. These types of volcanoes erupt in one large explosion, so they do not have the distinguishable "sloping" structure seen in regular volcanoes; this makes them extremely hard to identify.
The irregularly shaped craters in the Arabia Terra region are excellent candidates for ancient supervolcano calderas. Siloe Patera is characterized by two depressions surrounding by steep-sided walls and collapse features. These two depressions may represent two separate eruptions caused by collapses that occurred as the pressurized magma was released.
A closer look at Siloe Patera has also revealed channels and gullies cut into the walls of the feature that may have been caused by ejecta from an impact or volcanic eruption. Arabia Terra is composed of "fine-grained, layered sulphate- and clay-bearing materials," which may have been deposited by lava and dust from volcanic eruptions.
"Without any doubt, more data and high-resolution coverage - and even in situ sampling - would be necessary to resolve this mystery. And since the gases released in supervolcano eruptions could have had significant effects on the martian climate, this is a topic of great interest," ESA stated.
