Tonopah Desert Tonopah Desert The Tonopah Desert is a small desert plains region of the Sonoran Desert, located west of Phoenix, Arizona. It is adjacent north of Interstate 10 and lies at the southwest intersection of the Hassayampa River with the Gila River. The Tonopah Desert is also just north of the Gila Bend Mountains massif which create the Gila Bend of the river. The Tonopah Desert is adjacent northwest of the small Palo Verde Hills on Centennial Wash. The Tonopah Desert is mostly east-west trending, small, approximately 30 mi long, and lies at the plains of low elevation mountains north; the
Painted Desert (Arizona) desert is composed of stratified layers of easily erodible siltstone, mudstone, and shale of the Triassic Chinle Formation. These fine grained rock layers contain abundant iron and manganese compounds which provide the pigments for the various colors of the region. Thin resistant lacustrine limestone layers and volcanic flows cap the mesas. Numerous layers of silicic volcanic ash occur in the Chinle and provide the silica for the petrified logs of the area. The erosion of these layers has resulted in the formation of the badlands topography of the region. In the southern portions of the desert the remains of a