This image includes the southeast wall of a little crater found a couple of hundred kilometers to the north of the giant Hellas effect basin on Mars. The total crater itself has to do with 12 km in size; this image reveals a 5 x 10 km location.
The Colour and Stereo Surface Imaging System (CaSSIS) onboard the ExoMars Trace Gas Orbiter took the image on October 19, 2020.
When seen with CaSSIS’ color filters, the image reveals extraordinary variety in color. This variety is associated with the existence of numerous minerals that show light in a different way at various wavelengths. The light-toned deposits highlight the bedrock direct exposures of the location, which most likely consist of ancient clay-rich minerals that would have formed in the existence of water. Also noticeable are wind-blown sandy deposits that form ripples on the flooring of the crater. Their unique tan color suggests that they consist of iron-oxide minerals.
The ExoMars program is a joint venture in between ESA and Roscosmos.
The image was included by Science Advances online in February 2021.
Reference: “Transient HCl in the atmosphere of Mars” by Oleg Korablev, Kevin S. Olsen, Alexander Trokhimovskiy, Franck Lefèvre, Franck Montmessin, Anna A. Fedorova, Michael J. Toplis, Juan Alday, Denis A. Belyaev, Andrey Patrakeev, Nikolay I. Ignatiev, Alexey V. Shakun, Alexey V. Grigoriev, Lucio Baggio, Irbah Abdenour, Gaetan Lacombe, Yury S. Ivanov, Shohei Aoki, Ian R. Thomas, Frank Daerden, Bojan Ristic, Justin T. Erwin, Manish Patel, Giancarlo Bellucci, Jose-Juan Lopez-Moreno and Ann C. Vandaele, 10 February 2021, Science Advances.