New class of landform detected on Mars

   Mar 23, 12:35 pm

Washington, March 23 (ANI): University of Washington geologists have discovered an odd, previously unseen landform on Mars, which they believe could provide a window into the geological history of the red planet.

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.

They call the structures periodic bedrock ridges (and they use the abbreviation PBRs to evoke a favourite brand of beer).

The ridges look like sand dunes but, rather than being made from material piled up by the wind, the scientists say the ridges actually form from wind erosion of bedrock.

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

He believes the ridges, while still bedrock, are composed of a softer, more erodible material than typical bedrock and were formed by an unusual form of wind erosion that occurs perpendicular to the prevailing wind rather than in the same direction.

He contrasts the ridges with another bedrock form called a yardang, which has been carved over time by headwinds. A yardang has a wide, blunt leading edge in the face of the wind, and its sides are tapered so that it resembles a teardrop.

In the case of periodic bedrock ridges, Montgomery believes 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.

Spacing between ridges depends on how long it takes for the winds to come back to the surface, and that is determined by the strength of the wind, the size of the deflection and the density of the atmosphere, he said.

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

"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 said.

"You could actually go back and look at some earlier eras in Martian history, and the wind would have done us the favour of exposing the layers that would have that history within it," he said.

"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 added.

There could be landforms on Earth that are somewhat similar to periodic bedrock ridges, Montgomery said, but to date there's nothing exactly like it, largely because there are not many bedrock landscapes on Earth in which wind is the main erosion agent.

"There are very few places ... where you have bedrock exposed at the surface where there isn't also water that is carving valleys, that's shaping the topography," he said.

"Mars is a different planet, obviously, and the biggest difference is the lack of fluvial action, the lack of water working on the surface," he added.

The discovery has been recently reported in the Journal of Geophysical Research, a journal of the American Geophysical Union. (ANI)

NASA discovers ozone-depleting compound in Earth's atmosphere Aug 21, 5:40 pm
Washington, Aug 21 (ANI): NASA has discovered large amount of an ozone-depleting compound from an unknown source decades, after the compound was banned worldwide, in the Earth's atmosphere.
Full Story
Scientists discover potential signs of life on Mars Aug 20, 12:59 pm
Washington, Aug 20 (ANI): Scientists have discovered mineral-rich structure on Mars that might be the evidence of niche environment on the planet's subsurface that could support life.
Full Story
Interstellar dust grains may explain origin of solar system Aug 19, 1:39 pm
London, August 19 (ANI): Scientists are hopeful that the interstellar dust grains gathered by the NASA Stardust spacecraft and brought back to Earth will help in better understanding the complexities of the solar system's formation.
Full Story
Immune system becomes 'confused' during spaceflight Aug 19, 1:14 pm
Washington, Aug 18 (ANI): A new study has revealed that spaceflight may temporarily alter the immune system of crew members flying long duration missions aboard the International Space Station, leaving it "confused".
Full Story
Comments

LATEST STORIES
TOP VIDEO STORIES
PHOTO GALLERY