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ShareWashington: A recent NASA report has suggested that Martian water most likely flowed as slurries of mud rather than trickling streams.
According to ABC News, the report, which compared signs of recent water activity in gullies on Mars with similar deposits on Earth, has implications for searching for evidence of water on the red planet.
It could also indicate whether Mars has had liquid water within the last decade.
In 2004 and 2005, images taken by NASA's Mars Global Surveyor showed evidence of what looked like fresh flows of liquid; light-toned patches on the crater walls in the Terra Sirenum and the Centauri Montes regions of southern Mars.
The features hadn't been seen in previous photos of the region taken in 2001.
Scientists debated whether the patches were evidence of water flows, but their origin remains controversial.
This is because spectrographic images, which reveal the mineralogy of the surface, showed no hydrated minerals (such as clays) and no salts left behind by the water, which would have quickly evaporated in the dry Martian air.
An analysis led by Dr Jennifer Heldmann of NASA's Ames Research Center in California, suggests the flow may have been mud.
To better understand the Martian features, the team compared them to similar light-toned patches in the Atacama Desert, an extremely arid desert along the west coast of South America.
"The new light toned deposits seen in association with gullies on Mars in Terra Sirenum and Centauri Montes show striking similarities in geomorphology with the new Atacama Desert gully deposit. The deposits on Earth and Mars are both thin deposits that are more light toned than the surrounding terrain," according to the researchers.
"By analogy to the Atacama deposit, it is possible that the Martian deposits were formed by the action of liquid water, most likely by a soil and water fluidised slurry which flowed downslope," they added.
The Atacama mudflows were generated by a rare rainfall event nine days before the researchers collected their data.
This data revealed the light tone was caused by the difference in the size of the particles in the mudflows compared to the coarser-grained surrounding terrain.
According to the researchers, this indicates the best way to look for water on Mars is not to look for differences in the composition of the sediments, but in the size of the particles.
