January 28, 2016

Six-kilometre-deep canyons in the 'Labyrinth of the Night'

Directly to the west of the gigantic graben system of Valles Marineris on Mars, lies a no less impressive region called Noctis Labyrinthus – the Labyrinth of the Night. It consists of a labyrinth of intersecting valleys and canyons up to six kilometres deep. Extending over 1200 kilometres east to west, it is almost the same length as the River Rhine. The images shown here were acquired in July 2015 by the High Resolution Stereo Camera (HRSC) operated by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and show part of the northeast edge of the labyrinth.

Some smaller side valleys between deeply cut grabens can also be seen in images 1, 2 and 4. However, giant mesas, the plateaus of which represent the original surface level of the Martian highlands, dominate the whole region. With a width of approximately 30 kilometres, the valley in the right half of the image is one of the widest in the entire labyrinth. Elsewhere, the canyons narrow to a few kilometres. If an astronaut were to stand at the bottom of these valleys, the towering escarpments rising several kilometres on either side would be quite a spectacular scene.

The formation of this canyon system is linked to the uplifting of the surface in the Tharsis region, which lies further to the west. Intensive volcanism led to tectonic stress in the Martian crust, and with it, the fracturing of large areas of the surface. At the same time, parts of the surface sank between blocks of terrain that were pulled apart. The largest volcanoes on Mars are also found in the Tharsis-Region.

Upslope migration of dune crests

In many places, the steep valley slopes and the valley floor are covered with extensive landslides. Elsewhere, as can be seen well in these images on closer inspection, the slopes appear to be largely covered by massive wind deposits. The regular linear structures on the valley slopes visible on the left and right edges of the images can be interpreted as dune crests. From the alignment of the crests, it can be deduced that in some places, sand has been transported down the slope, while in other places, uphill transportation of the dune sand has taken place.

In every case, these surface structures created by the wind are no longer active. This is indicated not only by the consistent covering of red Martian dust (active dunes on Mars would be dark grey in appearance as they generally consist of old volcanic dust), but also by the presence of several small impact craters, visible in the lower right edge of the image, for example. In the event of a meteorite impact in an active dune, no crater would be left in the fine, loose material as the sand would trickle into the depression that was formed and immediately fill it back up again. Furthermore, any depression that was left would quickly be obliterated by sand moved by the wind. If the dunes are old and have hardened over the course of time, however, meteorites can leave small craters behind. The approximate age of the sand dunes can be determined If the crater sizes and frequencies are accurately measured. The small number and sizes of the craters found here indicates a relatively young age for the dunes.

  • Image processing

    The HRSC system acquired these images on 15 July 2015 during Mars Express orbit number 14,632. The region is located at six degrees south and 265 degrees east. The image resolution is approximately 16 metres per pixel. The colour plan view (image 1) was produced by the nadir channel, which is directed vertically down onto the surface of Mars, along with the colour channels; the oblique perspective view (image 3) was calculated using data acquired by the HRSC stereo channels. The anaglyph image (image 4), which conveys a three-dimensional impression of the landscape when viewed through red-blue or red-green spectacles, was composed using data acquired by the nadir channel and one stereo channel. The colour-coded plan view (image 2) is based on a digital model of the regional terrain, from which the landscape topography can be derived.

  • The HRSC experiment

    The High Resolution Stereo Camera (HRSC) was developed at DLR and built in collaboration with industrial partners (EADS Astrium, Lewicki Microelectronic GmbH and Jena-Optronik GmbH). The science team, which is headed by Principal Investigator (PI) Ralf Jaumann, consists of 52 co-investigators from 34 institutions in 11 countries. The camera is operated by the DLR Institute of Planetary Research in Berlin-Adlershof.

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Elke Heinemann

Digital Communications
German Aerospace Center (DLR)
Corporate Communications
Linder Höhe, 51147 Cologne
Tel: +49 2203 601-1852

Prof. Dr. Ralf Jaumann

Freie Universität Berlin
Institute of Geological Sciences
Planetary Sciences and Remote Sensing
Malteserstr. 74-100, 12249 Berlin

Ulrich Köhler

German Aerospace Center (DLR)
Institute of Planetary Research
Rutherfordstraße 2, 12489 Berlin