The basement in the region is formed by plutonic rocks of Mesozoic age, metasedimentary and metavolcanic rocks which crop out in the White Mountains and the Sierra Nevada; the valley floor is covered with alluvium. Tectonically, Owens Valley is a graben formed by the movement of the Sierra Nevada-Great Valley block with respect to the rest of North America. Farther south lies the Coso volcanic field, which is also geothermally active unlike Big Pine volcanic field.