Geologist Find Unusual Land Formation On Mars
March 23, 2012

Geologists Find Unusual Land Formation On Mars

Geologists at the University of Washington found that a previously unseen landform on Mars could help provide a window into the geological history of the Red Planet.

The "periodic bedrock ridges", or PBRs, look like sand dunes, but the scientists say that they are actually made from wind erosion of bedrock.

"These bedforms look for all the world like sand dunes but they are carved into hard rock by wind," David Montgomery, a UW professor of Earth and space sciences, said in a press release. "It is something there are not many analogs for on Earth."

Montgomery said he believes the ridges are composed of a softer material than typical bedrock, and were formed by an unusual form of wind erosion.

He said high surface winds on Mars are deflected into the air by a land formation, and they erode the bedrock in the area where they settle back to the surface.

The spacing between ridges, according to Montgomery, depends on how long it takes for the winds to come back to the surface.  He said this is determined by the strength of the wind, the size of the deflection and the density of the atmosphere.

Montgomery said the discovery is important because if the ridges were created by wind depositing material, then "you're not going to have information from any prior history of the material that is exposed at the surface."

"But if it's cut into instead, and you're looking at the residual of a rock that has been eroded away, you can still get the history of what was happening long ago from that spot," Montgomery added.

He said you could look back at earlier eras in Mars by looking at the layers of history the wind has helped pull back.

"There are some areas of the Martian surface, potentially large areas, that up until now we've thought you couldn't really get very far back into Mars history geologically," he said.

The research was published in the Journal of Geophysical Research on March 9.


Image Caption: Images from the High Resolution Imaging Science Experiment on NASA's Mars Reconnaissance Orbiter show exposed rock strata in periodic bedrock ridges on the floor of the West Candor Chasma on Mars.