Deep Canyons and Giant Landslides
The Noctis Labyrinthus region (Latin for “labyrinth of night”) is located between the western edge of Valles Marineris and the Tharsis upland. It has a length of 1190 km and is characterized by a system of deep and steep-walled valleys formed by faulting. Many of the valleys show the classical appearance of so-called graben. A graben is a part of the crust that has subsided in relation to the blocks on either side. The faults typically dip toward the center of the graben from both sides. The fractures are witnesses of extensional tectonics. The intense volcanism in the Tharsis region was associated with an up-arching of large areas. This process resulted in tectonic stress, causing the crust to thin out and lead to the graben formation. Large plateaus representing the original surface level dominate the region. The intersecting canyons and valleys are up to 30 kilometers wide and up to six kilometers deep. There is no comparable landscape on Earth, nor on any other planet or moon in the Solar System. In many places, gigantic landslides can be found, covering the steep valley slopes and the valley floors. In other places, large linear structures can be found on the valley slopes. These structures are wind-blown sand deposits, accumulating to large dune fields. The alignment of the dune crests indicates that in some areas the sand was transported downslope, while in other places, the dune sand has been blown uphill.