Medusae Fossae Formation and the northern lowlands

The Medusae Fossae Formation (MFF) is hypothesized to be an enormous deposit of pyroclastic material, generated during explosive eruptions from unknown volcanic vents. Investigation of these materials has been hampered for decades by dust that hides the surface rocks from easy remote observation. The MFF materials have been sculpted by sand and wind into massive eroded ridges called yardangs, with layers of variably erodible rock exposed in many places. Apollinaris Mons is hypothesized to be a potential source for MFF deposits, but the immense volume of the MFF materials far exceeds the volume of this volcano. The northern lowland plains have many examples of explosion pits called pseudocraters, interpreted to be the result of hot volcanic materials being emplaced on top of subsurface ice or wet materials.