In the upper left of the image one can find the Valles Marineris canyon system whose origin and development is closely related to the Tharsis volcanic province. Dynamic models show that the emplacement of the Tharsis rise onto the crustal dichotomy boundary, which is a topographic step separating the northern lowlands from the southern highlands, led to tension and crustal rupture at the present-day location of Valles Marineris. As a consequence, intrusives of molten rock filled the fissures created by the crustal rupture, and formed so called dikes which acted to destabilize and decouple the crustal blocks from each other. Subsidence of the blocks then created troughs and canyons that later grew in width by the collapse of wall material. The web-like pattern of troughs in Noctis Labyrinthus at the western end of Valles Marineris can be explained by interacting stress patterns.