More Evidence Found for Water on Mars

[Doondoo]

An orbiting spacecraft has sent back new evidence for the presence of water on Mars.



Images from a camera aboard NASA's Mars Reconnaissance Orbiter show alternating layers of dark- and light-toned rock in a giant rift valley.

Within those deposits are a series of linear fractures, called joints, that are surrounded by "halos" of light-toned bedrock, according to researchers from the University of Arizona.



Lead author Chris H. Okubo said the "halos" indicate areas where fluids, probably water, passed through the bedrock. Minerals in the fluid strengthen and bleach the rock, he said, making it more resistant to erosion than other areas.

"On Earth, bleaching of rock surrounding a fracture is a clear indication of chemical interactions between fluids circulating within the fracture and the host rock," Okubo and co-author Alfred S. McEwen reported in the paper.



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