By Xinhua
Beijing : Scientists said surface features of the Red Planet hint at a watery past where torrents of groundwater carved out deep canyons, formed sweeping fans of sediment and cemented together huge fault lines, media reported Tuesday.
“Groundwater probably played a major role in shaping many of the things we see on the Martian surface,” said George Postma, a sedimentologist at Utrecht University in the Netherlands.
Scientists think a massive ocean once covered one-third of Mars, and recent photographs suggest that pockets of water may still be hidden beneath the planet’s surface. Water is crucial for life as we know it, so signs of underground water now — and more extensive amounts of water in the past — both suggest Mars was or might still be habitable, at least to microorganisms.
Postma said such reservoirs of water probably carved out canyons, rapidly depositing step-like layers of sediment in Martian impact craters across the planet.
“Groundwater is a crucial reservoir in Mars’s global water cycle and plays an important role in … alteration of bedrock,” said Allan Treiman, a scientist at the Lunar and Planetary Institute in Houston.
In Valles Marineris, where about 2,500 miles (4,000 kilometers) of 6-mile-deep (10-kilometers) chasms dwarfing the Grand Canyon stretch over Mars, Allan Treiman thought he has located more evidence of groundwater at work.
The Valles Marineris canyons formed when massive slabs of rock both lifted up and sunk, creating fault lines in the process. Spacecraft imagery of the landscape shows the crevices as ridges, which Treiman thinks were filled with mineral-rich groundwater between 3.5 billion and 1.8 billion years ago.
“This interpretation implies that liquid water was stable at or near Mars’s surface when the fault zones were cemented,” Treiman said, noting that only a “warm wet” climate on Mars could have made the deposits possible.
“The presence of liquid water is important in current ideas of Mars’s history,” Treiman said, “and central to Mars’s potential for life.”