Martian formations suggest underground water surgesFebruary 21st, 2008 - 2:35 pm ICT by admin
New York, Feb 21 (IANS) Many unique formations on Mars suggest that they were formed millennia back by water welling up rapidly from deep within the red planet. Some of these formations, which resemble gigantic fans, have steps going down to a basin, and researchers have disputed how they were formed since their discovery three years ago.
But a team of scientists from the US and the Netherlands now believe they were formed by water gushing from within Mars.
The team also believes that their formation took perhaps only tens of years, and not hundreds or millions of years estimated for other Martian hydrologic events.
The scientists, whose findings have been published in the latest issue of the journal Nature, said the formations must have required a lot of water. And it was a one-time event - as the basin did not refill.
“Water volumes would be between that of the Mississippi river over the course of 10 years or the Rhine river flowing for 100 years into a 62-mile-wide basin,” said Erin R. Kraal, research scientist at Virginia Tech.
“We suggest the water was released internally, such as hydrothermal water suddenly pushed to the surface,” Kraal said.
As there are no similar formations on earth, the researchers came to their conclusions by creating a room-sized sediment flume and digging a crater in sand. They then simulated water flow into the crater.
“As the fan and the water level intersected, the steps appeared,” Kraal said.
“As the water flows in through a channel, it erodes the sediment. The water fans out and deposits the transported sediment as deltas, building steps down into the basin.”
Once they established what had to happen to make a stepped fan in the lab, the scientists created sediment transport models and studied the morphology of the fans on Mars using satellite images and topographical date from the Mars Orbiter Laser Altimeter (MOLA).
Based on fans of 20 kilometres in basins of 100 kilometres, they calculated the conditions for the creation of a stepped fan.
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