Unearthed Silica Deposits Imply Watery Past for Mars

A no-longer functional wheel on the Spirit rover provided scientists with the best evidence yet that Mars once held water. Dragged along by the rover, the wheel unearthed a soil deposit composed of about 90% pure silica.

"You could hear people gasp in astonishment," said Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the Mars rovers' science instruments. "This is a remarkable discovery. And the fact that we found something this new and different after nearly 1,200 days on Mars makes it even more remarkable. It makes you wonder what else is still out there." [..]

Doug McCuistion, director of NASA's Mars Exploration Program, said, "This unexpected new discovery is a reminder that Spirit and Opportunity are still doing cutting-edge exploration more than three years into their extended missions. It also reinforces the fact that significant amounts of water were present in Mars' past, which continues to spur the hope that we can show that Mars was once habitable and possibly supported life."

Albert Yen, a geochemist at NASA's Jet Propulsion Laboratory, said that this new discovery provides some of the best evidence yet that the Gusev Crater contained or contains water. The silica could have been formed due to an interaction of soil and acid vapors from volcanic activity in the presence of water, or maybe from water in a hot spring environment.

The discovery likely wouldn't have happened had Spirit's wheel not been broken. Analysis of the disturbed soil deposits with Spirit's miniature thermal emission spectrometer -- which provides analysis of mineral compositions from a distance -- indicated that silica existed in the overturned soil, so the team decided to move closer. The silica deposits were confirmed by analyzing the soil with Spirit's alpha particle X-ray spectrometer.

The Mars rover team has plans to further study this soil, as well as that of the surrounding areas.

The newly discovered has been named after Gertrude Weise, a player in the All-American Girls Professional Baseball League.

Mars Rover Spirit Unearths Surprise Evidence of Wetter Past [NASA]