London, March 18 : Scientists have suggested that huge fountains of carbonated water once erupted on ancient Mars, hurling hailstones and mud several kilometers into the air.
According to a report in New Scientist, scientists led by Alistair Bargery of Lancaster University in the UK, said that they have found signs of ancient geysers on Mars that would have dwarfed even those in Yellowstone National Park in US.
Towering a couple of kilometres above the surface, Martian geysers rained hailstones and muddy water for several kilometres around, the scientists said.
The geysers erupted when bubbles of carbon dioxide forced underground water up to the surface through cracks, they added.
The evidence for this appears at two sites on Mars where cracks hundreds of kilometers long called Mangala Fossa and Cerberus Fossae stretch across the surface.
Both cracks are the starting points for broad channels that appear to have carried huge quantities of water - between 10 and 100 times the flow of the Amazon River. At least some of this water seems to have erupted onto the surface in the form of enormous geysers.
At Cerberus Fossae, water appears to have reached an area that is uphill from the crack and several kilometres away, based on the erosion of a slope there.
"A powerful geyser must have erupted from the crack to transport the water all that way," said team member Lionel Wilson.
According to Neather, based on the distance of the deposits from the cracks, the geysers must have thrown material outwards by at least 4 kilometres. The team calculates that Martian geysers could throw material up to twice this distance.
The secret to the power of the Martian geysers is that their source water seems to have come from very deep below the surface.
The overlying rock at Mangala Fossa appears to have slumped downwards when underground water pockets emptied out, and the amount of this slumping suggests the water pockets lay about 3 to 4 kilometres below the surface.
The pressure at such great depths means water would be able to hold large quantities of dissolved carbon dioxide, which may have come from underlying magma. Once a crack formed that connected the surface to the high-pressure water below, the water would have rushed upwards.
The resulting drop in pressure would have had the same effect as opening a shaken soda can. Expanding bubbles of CO2 would have caused the muddy water to shoot out in geysers at more than 400 kilometers per hour.