This image shows wind-eroded layered deposits in Aeolis Mensae, located close to the volcanic region of Elysium and near the boundary of the high-standing, heavily cratered southern hemisphere and the low, sparsely-cratered plains that cover most of the northern hemisphere of Mars.

Aeolis Mensae is well-known for its unusual features commonly related to wind activity on the planet’s surface. Several long, sinuous, and branching ridges have been exposed by wind erosion. Raised curvilinear ridges observed in this region, such as those shown here, are believed to be former stream channels now preserved in inverted relief.

On Earth, inverted relief occurs when formerly low-lying areas become elevated because the original depression is filled with materials, such as lava, that are more resistant to erosion than the surrounding terrain. In the case of stream channels, the stream bed may contain larger rocks and/or sediments that have been cemented by chemicals precipitating from flowing water, which remain while adjacent fine material is blown away by the wind. In this location, it is most likely that water once flowed through this channel and deposited sediments that eventually filled the channel and became cemented. Over time, wind eroded the surrounding surface leaving the remnant channels exposed as raised curvilinear ridges.

Surrounding the inverted channels are several shorter, linear, streamlined ridges oriented roughly south/north. These are yardangs or streamlined remnants of material shaped by the action of sand-blown sediments that eroded away weaker material. The orientation of the yardangs indicates the primary wind direction. Landforms such as these are common in desert areas on Earth. Portions of the larger curvilinear ridges appear to be eroding into yardangs.


Written by: Maria Banks

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible: Image: NASA/JPL/University of Arizona

For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.