Yardangs are sharp ridges formed by wind erosion. On Earth they usually occur in arid areas with soft deposits and strong winds. Though their shapes may vary, the classic yardang mimics the form of the overturned hull of a ship.
The Martian winds have sculpted yardangs and other erosional patterns in the layered deposits on the floor of an impact crater.
Mars Reconnaissance Orbiter, HiRISE NASA/JPL/University of Arizona image
The wind has shaped these sharp ridges.
Mars Odyssey, THEMIS
NASA/JPL/Arizona State University
This image illustrates both wind deposition and erosion. Large sand ripples have formed perpendicular to the wind-carved yardang ridges, which trend from the upper left to lower right.
Mars Global Surveyor, MOC
NASA/JPL/Malin Space Science Systems image
Dark and light-colored streaks are often found downwind of craters and other obstacles. Depending on the wind's path and speed, the streaks may form by deposition of fine particles or by erosion revealing a darker surface beneath.
These wind streaks are located atop lava flows. The large streak is nearly 20 kilometers (12 miles) long.
Mars Odyssey, THEMIS
NASA/JPL/Arizona State University image
Bright streaks deposited downwind of craters in the Syrtis Major region.
Mars Odyssey, THEMIS
NASA/JPL/Arizona State University image
Changing wind directions produce streaks with different orientations.
Mars Odyssey, THEMIS
NASA/JPL/Arizona State University image
