These dark hills of windblown sand are on the small side for being Martian dunes. The smallest is about 88 meters across (for reference the smaller dunes found on Earth are usually one-quarter this size). What’s interesting is the variation in their slip faces: some are steep that are easy to find, showing that the wind is blowing mainly southward. That must be the case because we’re looking at small section of a dune field, most of which is off the edge of the image to the bottom.

But then there’s a big one with weirdly shaped slip face: it looks like a bird with an outstretched wing. For some of these dunes, the slip faces are harder to find. Some appear to wrap around the dunes, suggesting that a wind blowing from the upper right to lower left might also sometimes be able to create a slip face. And one on the lower left has no slip face at all.

ID: ESP_062583_2230
date: 2 December 2019
altitude: 297 km

https://uahirise.org/hipod/ESP_062583_2230
NASA/JPL-Caltech/UArizona
#Mars #science #NASA