Further evidence that water once flowed on Mars found

NASAs Spirit rover has found evidence of past volcanic activity on the Martian Plateau known as Home Plate, which astronomers say, supports earlier findings indicating presence of water either at or beneath the planets surface at some point of time.

Washington, May 10 : NASA's Spirit rover has found evidence of past volcanic activity on the Martian Plateau known as 'Home Plate', which astronomers say, supports earlier findings indicating presence of water either at or beneath the planet's surface at some point of time.

Data collected during the rover's initial pass across the 90 metre wide plateau also supports this theory, NASA researchers say.

According to Steve Squyres, the Spirit mission's principal investigator and the Goldwin Smith Professor of Astronomy at Cornell, Home Plate shows evidence of long-past explosive volcanic activity.

Chemical analysis of rocks also shows that it is made of the same material (basalt) as volcanic rocks around it, he said.

"That the rocks at Home Plate are basalt -- not a material normally associated with explosions - also hints that water was involved. When basalt erupts, it often does so as very fluid lava, rather than erupting explosively. But a notable exception comes when hot basalt meets water to cause a steam-driven explosion," Squyres said.

"The bomb sag -- now dry, but shaped as if the rock sitting in it landed with a splat instead of a thud -- is a second hint that the surface was once wet. A third is the material's high chlorine content, which may point to past exposure to a briny fluid," he added.

According to him, any volcanic activity at Home Plate probably happened billions of years ago -- but part of what makes it intriguing, is its similarity to regions on other parts of the planet.

"There are lots and lots of places on Mars where, from orbit, you see layered deposits locally that kind of look like this, and so it really raises the possibility that a lot of these things all over the planet could be explosive volcanic deposits," he said.

The findings appear in the May 4 issue of the journal Science.

ANI