Mars images suggest dried-up lakes, sedimentary rock
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Examples of layered outcrop landscapes photographed by Mars Global Surveyor (Images copyright Science Magazine)
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SAN DIEGO, California (CNN) -- Was Mars once a land of lakes? And could those dried up lake beds harbor fossils of
life-forms that possibly once lived there?
Those are the questions scientists are asking themselves as they pore over new close-up images of Mars that show ancient sedimentary rock formations on the planet's surface.
The rock formations appear to be layered outcroppings, similar to the shale-like sedimentary rock found on Earth. On this planet, such sedimentary rock formations have proved to be rich fossil beds. That's because ancient plants and animals got sandwiched between the rock layers as they were forming, preserving the fossilized remains over geological time.
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Scientists speculate that the same kind of thing could have happened with these sedimentary rocks on Mars, if any life existed there when these rocks formed between 3.5 billion and 4.3 billion years ago.
The images were taken by the Mars Orbiter Camera (MOC) aboard the orbiting Mars Global Surveyor spacecraft. They were analyzed by Michael Malin and Kenneth Edgett of Malin Space Science Systems in San Diego, who are reporting their findings in this week's edition of the journal Science.
The research team said there are numerous ways the sedimentary rock could have formed. Wind, water, volcanic activity, even an asteroid impact can create sedimentary layers. None of those processes can be ruled out in attempting to explain how and why they formed on Mars.
But Malin and Edgett suggest a likely scenario would involve these layers of rock forming after lakes of water pooled in basins, craters and chasms on the martian surface.
"Some of the MOC images of these outcrops show hundreds and hundreds of identically thick layers, which is almost impossible to have without water," Malin said in a statement.
But the researchers stress that they do not have all the answers, likening the geologic history of Mars to a jigsaw puzzle.
"In the center of the puzzle, we have these layered rocks, which are good evidence of an extremely dynamic environment," Malin said.
"On either side of this well-developed puzzle piece, we have mysteries. In any case, Mars sedimentary rocks suggest a very active early history for the planet."
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RELATED SITES:
NASA
Mars Global Surveyor
NASA Jet Propulsion Laboratory
Malin Space Science Systems
Science Magazine
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