Geologist John Mustard of Brown University, said "There was apparently pervasive water present during the first 600 to 700 million years."
Mustard's team studied data returned by the Compact Reconnaissance Imaging Spectrometer for Mars, an instrument designed to find
traces of minerals that interact with water. Earlier studies have found evidence of ancient gushers, and the Mars Phoenix Lander recently found ice. But Mustard's analysis provides the clearest picture yet of planet-wide hydrological impacts and most tantalizingly, CRISM showed widespread deposits of clay-like minerals that form only at relatively low temperatures.
Ancient Martian oceans may have been salty, but at least they weren't boiling. And perhaps, said Mustard, they weren't dead. "I think the prospects for present life were dim, but for past life, during this habitable era, they were really quite good," he said.
As for whether evidence of life will remain after four billion years, Mustard said that "it's probably better-preserved on Mars than on the Earth, where plate tectonics has recycled the crust."
He continued, "On Mars, many more elements from that early history are still present. And we do think whiffs of life are preserved in the Earth record, so I think Mars stands a good chance of preserving signatures, if they ever existed."
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