Water has played large role in shaping Martian landscape

February 6th, 2009 - 12:29 pm ICT by ANI  

Washington, Feb 6 (ANI): In a new research, scientists have determined that geologic features in Martian craters suggest deposition and flow of water and ice, which is further evidence for the large role that water has likely played in shaping the landscape of the Red Planet.

The research was done by scientists at the Tucson-based Planetary Science Institute (PSI) in the US.

Their results provide strong evidence that multiple wet and/or icy climate cycles have shaped the topography of the planets large craters.

Studying crater degradation in potentially ice-rich environments is vital to understanding the geology of craters and their surroundings, as well as for determining whether the ice comes from the atmosphere or from below the ground, said Daniel Berman, a PSI associate research scientist and lead author of the research paper.

Berman, along with PSI Senior Scientist David Crown and PSI Research Scientist Leslie Bleamaster III, surveyed the geologic features in two sets of mid-latitude craters.

Each set included about 100 craters, with the first set in the Arabia Terra region of the northern hemisphere and the second set in an area east of Hellas basin in the southern hemisphere.

The researchers selected craters that are greater than 20 km (about 12.5 miles) in diameter that have been completely or nearly completely photographed by cameras on various spacecraft, including the Mars Odyssey THEMIS VIS camera, the Mars Global Surveyor Mars Orbiter Camera, and the Viking Orbiter cameras.

They looked specifically for the following erosional or depositional features, the number and sizes of those features, and how the features are oriented.

Berman found that lobate flows, gullies, and arcuate ridges on the crater walls between latitudes of 30 to 45 degrees face the pole in their hemisphere, whereas equator-facing orientations are more common than pole-facing ones at latitudes between 45 and 60 degrees.

In the southern study area, narrow channels generally had pole-facing orientations, whereas wider valleys generally have equator-facing orientations.

The features pole-facing or equator-facing orientations could result from uneven heating of the crater walls.

Ice on walls that get more sunlight would melt faster, causing more water to flow and form the gullies and other features.

Further evidence for flowing ice is found on the crater floors, Berman observed. He found that the floors of small craters slope away from the walls that exhibit erosional/depositional features toward the more pristine ones.

These slopes have inclines of about 0.5 to 3 degrees. This suggests that ice-rich materials flowed from one crater wall to the other. (ANI)

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