Golden Canyon and the Red Cathedral. Fine-grained sedimentary rocks form among ancient lake deposits. Protected by darker clay and mud layers that inhibit erosion and help create ridges and ravines, the "badlands" are created. Red color of Cathedral is produced by oxidation of iron. Death Valley National Monument Est. February 11, 1933. Est. as Death Valley National Park in 1994; 5,270 square miles (13,649 km2). Inyo County, CA.