Western Portion of Acheron Fossae

Located north of Olympus Mons and west of Alba Patera, Acheron Fossae provides a record of early tectonic activity in the Tharsis region. Acheron Fossae is a relatively high standing region characterized by multiple subparallel graben. As seen in the image, the graben trend generally to the northwest. The entire area predates the Alba Patera flows (which embay the eastern most Acheron grabens) and the Olympus Mons volcano (one of the youngest Tharsis features). The subdued nature of the highstanding hills, the erosion the graben walls, the eroded rims of all the visible craters, and the wind etching of the flat surfaces all help indicate the great age of Acheron Fossae. http://photojournal.jpl.nasa.gov/catalog/PIA04034