NASA spacecraft finds impact glass on Mars

WASHINGTON: A NASA spacecraft has detected deposits of glass on Mars which were formed by asteroid impacts and may hold signs of ancient life on the red planet.

Formed in the searing heat of a violent asteroid impact, the glasses can encapsulate and preserve biological material for millions of years on Earth, and can also serve as a substrate for microbial life.

A previous study led by geologist Peter Schultz from Brown University that was published last year had found organic molecules and even plant matter entombed in glass formed by an impact that occurred millions of years ago in Argentina.

Schultz suggested that similar processes might preserve signs of life on Mars, if indeed they were present at the time of an impact.

These impact glasses are thus an important target to search for signs of ancient life on Mars, but until now they have not been definitively detected on the Martian surface.

Now, Kevin Cannon and Jack Mustard from Brown University have shown that large glass deposits are present in several ancient yet well-preserved craters scattered across the Martian surface.

To identify minerals and rock types remotely, scientists measure the spectra of light reflected off the planet's surface. But impact glass does not have a particularly strong spectral signal.

In the lab, Cannon mixed together powders with a similar composition of Martian rocks and fired them in an oven to form glass. He then measured the spectral signal from that glass.

Once he had the signal from the lab glass, he used an algorithm designed to pick out similar signals in data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), which flies aboard NASA's Mars Reconnaissance Orbiter.

The technique was able to pinpoint deposits around several crater central peaks, the craggy mounds that often form in the centre of a crater during a large impact.