London, March 27 (ANI): Scientists at NASA have identified dozens of mounds or domes in the northern plains of Mars, which they say bear a striking resemblance to mud volcanoes.
According to a report by BBC News, the domes on the Red Planet were detected using images taken by NASA's Mars Odyssey spacecraft, and Carlton Allen and Dorothy Oehler of NASA's Johnson Space Center in Houston.
Infrared data also show the domes cool more quickly at night than the surrounding rock, as one might expect if they were made of sediment.
Together with David Baker from Brown University, the researchers used instruments on NASA's Mars Reconnaissance Orbiter (MRO) to observe several of these structures in a northern region known as Acidalia Planitia.
Data from the MRO's Crism experiment indicate that the material in the domes is more oxidised than the rock of the surrounding plains.
This might suggest the presence of iron oxides, which form in the presence of liquid water.
They also took pictures of the structures with the HiRise camera on MRO; the images show the bright domes standing out against the dark basaltic rock of the surrounding plains.
Dr Allen told BBC News the structures resembled smooth cones with "no breaks", which visibly feathered out towards the margins.
The observations, he said, were consistent with material that is "smooth, soft and easily eroded".
On Earth, the largest concentration of mud volcanoes is in Azerbaijan and the adjacent Caspian Sea. But, they have been found at more than 40 sites on land and at more than 20 locations beneath the sea.
They are formed when pressurized gas and liquid from as much as several kilometers down, breach the surface. They belch out slurries of fluid, mud and rocks, as well as gases such as methane.
"In Azerbaijan, there is so much methane coming out that they can catch fire," said Dr Allen.
This raises the possibility that mud volcanoes could contribute to the methane observed in the Martian atmosphere.
Methane should last for only a short time in the atmosphere until it is destroyed by sunlight, so its continued presence means it is being replenished by some unknown process.
According to Dr Allen, the team had found no evidence that the domes could be active today, as most show clear evidence of erosion. But, he suggested they could have formed in the last 10 million years.
Researchers suggest that, if life does exist deep beneath the Martian surface, mud volcanoes could be one of the best ways to get at the evidence. (ANI)