For a dry, cold and dusty planet, Mars looks awfully wet in some spots. Mud volcanoes spotted by an international planetary science team look like the latest.
In the journal, Earth and Planetary Science Letters, the team led by Monica Pondrellia of Italy's Università d'Annunzio in Pescara, reports the discovery of about 250 mounds within the Red Planet's Firsoff Crater that appear to be mud volcanoes. The team discovered the mounds in images taken from the European Space Agency's Mars Express spacecraft and NASA's Mars Reconnaissance Orbiter.
Firsoff crater spans about 56 miles across and is almost a mile deep. Researchers have suggested that mud-spewing volcanoes may litter Mars for two decades, but the new finds inside the crater are the first ones that resemble Earth's mud volcanoes, says the study. About third of the mounds possess round mouths (typical of mud volcanoes according to the study) that average 43 feet across and are littered with lumpy boulder as big as 13 feet across.
The round mounds line the outermost fracture ring of the Firsoff impact crater. "This relationship suggests that the occurrence of the mounds is associated with pre-existing faults and fractures that might have acted as pathways for subsurface fluids," says the study:
Several investigators have detected methane, which on Earth is generally — although not exclusively — the gas associated with mud volcanoes, possibly due to seepage from the subsurface, in the Martian atmosphere through orbiter data and from ground-based telescopes. The possible current presence of methane in the atmosphere cannot be directly associated to putative mud volcanoes that were likely deposited in the uppermost Noachian, but it would suggest that methane seepage could be a plausible — although speculative — geological process that may have added to the driving mechanism for mud volcanism in the Firsoff crater.
Such methane may spring from water reacting with iron minerals below the Martian surface, the team speculates. Voila, mud springs.