The dark dunes of Moreux crater

Known for its wide swathes of rippling, textured, gently sloping dunes, Mars’ Terra Sabaea region is home to many fascinating geological features – including the prominent Moreux crater, the star of a new image from ESA’s Mars Express.

The crater is roughly three kilometres deep, and spans 135 kilometres from edge to edge. While the surrounding material is visible in hues of butterscotch and caramel, the crater’s walls are dark, resembling a smudged ring of charcoal, and dark brown-black dunes cover the crater floor. This darkness is thought to be a result of the dunes comprising sandy material rich in pyroxene and olivine, minerals with a typically dark appearance.

The dunes and flow features in Moreux crater are intriguing. Many of the features surrounding the central peak and southern region of the crater (to the left of the image) appear to have been formed by substantial and episodic glacial activity over the past few million years. Many other features, most notably the sickle-shaped dunes covering the crater floor, show signs of being eroded or formed by wind-related processes.

This image comprises data gathered on 30 October 2019 during orbit 20014. The ground resolution is approximately 16 m/pixel and the images are centred at about 44°E/42°N. This image was created using data from the nadir and colour channels of the High Resolution Stereo Camera (HRSC). The nadir channel is aligned perpendicular to the surface of Mars, as if looking straight down at the surface. North is to the right.