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Glass Discovered on Mars May Hold Signs of Ancient Life

Jun 09, 2015 11:08 AM EDT
This picture shows the peak of Alga Crater on Mars, where deposits of impact glass have been found. Green indicates the presence of glass.
(Photo : NASA/JPL-Caltech/JHUAPL/University of Arizona)

Glass deposits discovered in impact craters on the surface of Mars may hold signs of ancient life, adding to the growing evidence that the Red Planet was once habitable.

Formed in the intense heat of a violent asteroid impact, the Martian glass can capture and preserve biosignatures from any living organisms at the time of the collision for millions of years on Earth, providing a unique window into possible past life.

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

"The work done by Pete and others showed us that glasses are potentially important for preserving biosignatures. Knowing that, we wanted to go look for them on Mars and that's what we did here," Kevin Cannon, who led the new study, said in a news release

There is no reason to believe similar processes could not have taken place on Mars, especially given the fact that large glass deposits are scattered all over the planet.

Until now, glass deposits had not definitively been detected on our neighboring planet. In this study, researchers were successful in finding them in a number of ancient, but well-preserved impact craters in various spots on Mars thanks to a new technique.

In lab experiments, they determined what the spectral signal of Martian glass would be as sunlight bounced off it, then designed a computer algorithm that searched for that signal in the mass of data gathered by 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 center of a crater during a large impact.

Pictured: A possible Martian site (white circle) is the Nili Fossae trough. The blue-tinted Hargraves crater at the right (blue indicates a low topography) is known to contain impact glass.
(Photo : NASA/JPL-Caltech/Arizona State University) Pictured: A possible Martian site (white circle) is the Nili Fossae trough. The blue-tinted Hargraves crater at the right (blue indicates a low topography) is known to contain impact glass.

In fact, that the deposits were found on central peaks is a good indicator that they formed from an impact.

"The researchers' analysis suggests glass deposits are relatively common impact features on Mars," Jim Green, director of NASA's planetary science division, told The Washington Post. "These areas could be targets for future exploration as our robotic scientific explorers pave the way on the journey to Mars with humans in the 2030s."

One such target includes an impact crater called Hargraves, located near the 400-mile-long Nili Fossae trough, which is a leading candidate for a landing site for NASA's Mars 2020 rover mission. This region is teeming with ancient hydrothermal vents and has a crust that supposedly dates back to a time when the Martian surface was wetter.

Now, evidence of several glass deposits makes Hargraves the perfect spot for future exploration.

"If you had an impact that dug in and sampled that subsurface environment, it's possible that some of it might be preserved in a glassy component," said co-author Jack Mustard from Brown. "That makes this a pretty compelling place to go look around, and possibly return a sample."

This and other new findings described in the journal Geology suggest that these impact features are not only common, but are important targets for detecting past life on the Red Planet.

For more great nature science stories and general news, please visit our sister site, Headlines and Global News (HNGN).

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