Claritas Fossae is a densely-dissected highland terrain on the Tharsis Rise of Mars, located immediately south of the Tharsis Montes. The fossae of the Claritas Fossae region are many superposed swarms of graben.
Long narrow depressions on Mars are called fossae. This term is derived from Latin; therefore fossa is singular and fossae is plural. Troughs form when the crust is stretched until it breaks. The stretching can be due to the large weight of a nearby volcano. Fossae/pit craters are common near volcanoes in the Tharsis and Elysium regions. A trough often has two breaks with a middle sectionmoving down, leaving steep cliffs along the sides; such a trough is called a graben.