Mars Rover finds evidence of ancient volcanic explosion on Red Planet

The lower coarse-grained unit shows granular textures toward the bottom of the image and massive textures. Also shown in this false-color view is a feature interpreted to be a "bomb sag," which is 4 centimeters across. Image. Photo Credit: NASA/JPL-Caltech/USGS/Cornell

Washington, May 4 (ANI): NASA’s Mars Exploration Rover has found evidence of an ancient volcanic explosion at the rover’s landing site in Gusev Crater on the Red Planet.

The site, identified as “Home Plate”, is a plateau of layered bedrock approximately two metres high within the “Inner Basin” of Columbia Hills, the rover’s landing site.

Astronomers say this is the first explosive volcanic deposit identified with a high degree of confidence by Spirit or its twin Opportunity.

Steve Squyres of Cornell University, Ithaca, New York, the principal investigator for the rovers' science instruments said there is strong evidence to suggest that the layers are from a volcanic explosion.

“Evidence shows that the area near “Home Plate” is dominated by basaltic rocks. When basalt erupts, it often does so as very fluid lava, rather than erupting explosively. One way for basaltic lava to cause an explosion is for it to come into contact with water -- it's the pressure from the steam that causes it to go boom,” said Squyres.

NASA's Mars Exploration Rover Spirit acquired this high-resolution view of intricately layered exposures of rock while parked on the northwest edge of the bright, semi-circular feature known as "Home Plate." The rover was perched at a 27-degree upward tilt while creating the panorama, resulting in the "U" shape of the mosaic. (A) The northern edge of Home Plate, (B) the coarse-grained lower unit, (C) the fine-grained upper unit. Photo Credit: NASA/JPL-Caltech/USGS/Cornell

Astronomers suspect that the explosion that formed “Home Plate” might have been caused by an interaction of basaltic lava and water.

"When you look at composition of the rocks in detail, there are hints that water may have been involved. One example is the high chlorine content of the rocks, which might indicate that basalt had come into contact with a brine,” said Squyres.

He said one of the strongest pieces of evidence for an explosive origin for “Home Plate” is a ”bomb sag" preserved in layered rocks on the lower slopes of the plateau. Bomb sags form in volcanic explosions on Earth when rocks ejected skyward by the explosion fall into soft deposits, deforming them as they land.