The Sierra Pinacate is a shield volcano topped with and surrounded by cinder cones, basltic lava flows, and volcanic ash. It is located in the Mexican state of Sonora north of the resort and fishing port of Puerto Peņasco, on the Sea of Cortez, with it's northern flank crossing into Arizona. It covers over 600 square miles and the highest peak is over 3900 feet. The western edge of the volcanic field merges with the dunes of the Gran Desierto de Altar. The Sierra Pinacate and the Gran Desierto are now included in the El Pinacate y Gran Desierto de Altar Biosphere Reserve. In 1975 and in 1980 I was able to travel there with groups from U.C.Davis, during the spring breaks, and make these photographs.
Travels in the Sonoran Desert by Don Martinich is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.