2.1 Billion-Year-Old Martian Rock Discovered in Sahara Desert Contains Ancient Water

Posted by clnews _Featured_, Earth, Space, Videos Friday, January 4th, 2013

A 2.1 billion-year-old Martian rock offers scientists clues to to a period in the planet’s history when its climate finally changed. It is among the oldest known from the planet and matches findings from NASA rovers. The meteorite contains a concentration of water by weight about ten times higher than in any of the other 100 or so known Martian meteorites — those rare rocks that get ejected from the Martian surface into space when an asteroid hits the planet, and eventually find their way to Earth. It’s also the only known Martian sample on Earth that hails from a critical period, about 2 billion years ago, when Mars is thought to have become colder and drier than it was originally.

 

(Ron Cowen | Nature.com)

Meteorite carries ancient water from Mars

Rock is among the oldest known from the planet and matches findings from NASA rovers.

It may just look like your average rock, but in fact it’s an extra-special delivery from the red planet. Laboratory analysis has revealed that a specimen bought from a Moroccan meteorite dealer in 2011 is the first sample of Martian origin that is similar to the water-rich rocks examined by NASA’s rovers.

The meteorite, dubbed Northwest Africa (NWA) 7034, contains a concentration of water by weight about ten times higher than in any of the other 100 or so known Martian meteorites — those rare rocks that get ejected from the Martian surface into space when an asteroid hits the planet, and eventually find their way to Earth. It’s also the only known Martian sample on Earth that hails from a critical period, about 2 billion years ago, when Mars is thought to have become colder and drier than it was originally.

Carl Agee of the University of New Mexico in Albuquerque and his colleagues report their findings from samples of the meteorite in Science online today¹.

Water clues

“Agee and his collaborators have thrown open the door to a whole new part of Mars,” says planetary scientist Munir Humayun at Florida State University in Tallahassee, who was not involved in the study. The meteorite, he adds, is “the first of a new class of Martian meteorites that provides more direct clues to the surface history of Mars.”

Moreover, Humayun says, NWA 7034 may provide the only direct corroboration for the rovers’ observations for some time to come, as the fate of a long-delayed mission to bring samples of Mars back to Earth is still uncertain.

The elemental composition of the meteorite strongly resembles that of rocks examined in 2005 by NASA’s Spirit rover at Gusev Crater². Those rocks showed evidence of chemical alteration by interactions with liquid water, notes Agee. The composition of NWA 7034 also matches that of rocks studied by Curiosity, NASA’s newest rover, as described in preliminary reports from members of that mission.

Missing link

Dating from 2.1 billion years ago, NWA 7034 is the second-oldest Martian meteorite, and provides a “missing link” in the planet’s geological record, according to Agee.

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