Wind Etching

Today's VIS image shows a region of wind etched materials. In regions of poorly cemented surface materials it is possible to create large features due to just the action of the wind. The equatorial region between Olympus Mons and Apollinaris Mons is dominated by wind etched regions. The direction of the wind aligns with the ridges and valleys. The dominant wind direction in this region is southeast to northwest; however, the wind direction for the upper right of the image is to the other direction. The long linear wind etched valleys are called yardangs. These features are created by long term winds scouring a poor cemented surface material into linear ridges and valleys. These yardangs are part of the Medusa Fossae Formation. It has been suggested that this region of Mars provides a large percentage of the surface dust seen around the planet. Ash falls from nearby volcanoes may have been the source of the surface materials eroded into these and other wind eroded landforms.