This image features the southeast wall of a small crater located a few hundred kilometers to the north of the giant Hellas impact basin on Mars. The complete crater itself is about 12 km in diameter; this image shows a 5 x 10 km area.
The Colour and Stereo Surface Imaging System (CaSSIS) onboard the ExoMars Trace Gas Orbiter took the image on October 19, 2020.
When viewed with CaSSIS’ color filters, the image shows exceptional diversity in color. This diversity is related to the presence of various minerals that reflect light differently at different wavelengths. The light-toned deposits highlight the bedrock exposures of the area, which probably contain ancient clay-rich minerals that would have formed in the presence of water. Also visible are wind-blown sandy deposits that form ripples on the floor of the crater. Their distinctive tan color implies that they contain iron-oxide minerals.
The ExoMars program is a joint endeavor between ESA and Roscosmos.
The image was featured 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.