Sierra del Pinacate

Pinacate is a roughly 55 x 60 km volcanic field in the Sonoran desert of NW México. It contains numerous maars, tuff rings, and cinder cones of late-Pleistocene to Holocene age. The 2,000 km2 field is a prominent feature in this arid, sparsely populated region between the Arizona border and the head of the Gulf of California. An older volcanic period constructed the Santa Clara basaltic-to-trachytic shield volcano. This was followed by the eruption of more than 500 basaltic cinder cones and lava flows that cover the slopes of Santa Clara and the surrounding desert. Among the principal features of the field are two maars: Elegante crater (1.6 km wide) and Cerro Colorado (1 km wide). Legends from the Tohono O'odham people tell of eruptions, though accounts of ash-and-steam eruptions in the 20th century are questionable.