Hoodoos, Chiricahua National Monument NPS. Geology and Topography. The Sonoran Desert is composed of sedimentary, igneous, and metamorphic rocks with widely varying ages, from 2 billion year-old Precambrian outcroppings in Arizona to relatively recent (ca. 700 A.D.) volcanism in the Pinacate region near the international border. Between 20 and 40 million years ago, numerous volcanoes were active in the Sonoran Desert, resulting in large calderas (basins formed by volcanic explosions), lava vents, and cinder cones. This tectonic activity, coupled with intense heat from below, placed tremendous stress on the crusts underlying the Sonoran Desert, causing the horizontal and vertical movements that produced its characteristic Basin and Range topography.