The Specters of Mars

This image from NASA's Mars Reconnaissance Orbiter shows Malea Planum,a polar region in the Southern hemisphere of Mars, directly south of Hellas Basin, which contains the lowest point of elevation on the planet. The region contains ancient volcanoes of a certain type, referred to as "paterae." Patera is the Latin word for a shallow drinking bowl, and was first applied to volcanic-looking features, with scalloped-edged calderas. Malea is also a low-lying plain, known to be covered in dust. These two pieces of information provide regional context that aid our understanding of the scene and features contained in our image. The area rises gradually to a ridge (which can be seen in this Context Camera image) and light-colored dust is blown away by gusts of the Martian wind, which accelerate up the slope to the ridge, leading to more sharp angles of contact between light and dark surface materials.

https://photojournal.jpl.nasa.gov/catalog/PIA21784