Geology of the Horse Mesa Dam Quadrangle, Maricopa and Gila Counties, Arizona v. 2.0

The geologic map described in this study covers the Horse Mesa Dam Quadrangle (1:24,000) (Figure 1) (Sheets I-III). The area encompasses part of the northern Superstition Mountains and southern Mazatzal Mountains. Bedrock in this area consists largely of Proterozoic granitic and metamorphic rocks overlain by a thick sequence of early Miocene volcanic rocks. The study in one of a series of related geologic maps from the Arizona Geological Survey that cover the Superstition volcanic field and adjacent areas (Ferguson and Gilbert, 1997; Ferguson and Skotnicki, 1995; Skotnicki and Ferguson, 1995, 1996; Skotnicki and Leighty, 1997; Spencer and Richard, 1995). The rugged physiography of the area is dominated by drainages of the Salt River Canyon that crosses the north part of the map and is partially filled by Apache Lake. The Apache Trail (Arizona Highway 88) crosses the southern part of the map. The northwest part of the map was reached from Tonto National Forest road FR 401, which ends approximately one kilometer northwest from the northwest corner of the quadrangle. Report and geology of the Horse Mesa Dam Quadrangle, Maricopa and Gila Counties, Arizona, trhee map sheets, scale 1:24,000.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact azgs-info@email.arizona.edu