Painted Desert (Arizona) plateau's south border the Mogollon Rim, the north border of the Arizona transition zone. Owing to the strong rain shadow of the Mogollon Rim, the Painted Desert has a cold desert climate (Köppen "BWk"), with hot, dry summers and cold, though virtually snow-free winters. The annual precipitation is the lowest in northern Arizona and in many places is lower even than Phoenix. Much of the region is accessible only by foot or unpaved road though major highways and paved roads cut across the area. The towns of Cameron and Tuba City, both on the Navajo Nation, are two major settlements.
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