The canyon extends from the Noctis Labyrinthus region in the west to the chaotic terrain in the east. Most researchers agree that Valles Marineris is a large tectonic "crack" in the Martian crust, forming as the planet cooled, affected by the rising crust in the Tharsis region to the west, and subsequently widened by erosional forces. However, near the eastern flanks of the rift there appears to be some channels that may have been formed by water.