Lake Mead - Black Canyon

This view from US Highway 93 about 15 miles south of Hoover Dam is looking west from an overlook area in the Black Mountains into Black Canyon of the Colorado River near Willow Beach (at the north end of what is now Lake Mohave). Black Canyon cuts through dark, late Tertiary-age volcanic rocks that overlie or are in faulted contact with ancient Precambrian-age crystalline basement rocks (gneiss, schist, and granitic rocks). These ancient rocks are exposed along the canyon and in the adjacent mountains in the Willow Beach area. The slope extending to the lakeshore in the foreground is an incised alluvial fan. Washes expose underlying Quaternary sedimentary deposits and locally some of the volcanic rocks (Beard and others, 2007).