Geologic Map of the Painted Rock Mountains, Maricopa County, Arizona, scale 1:24,000.

The Painted Rock Mountains are about 15 miles west of the town of Gila Bend in southwestern Maricopa County, Arizona (Fig. 1). The narrow north-south trending mountain range is approximately 12 miles long and 2 to 4 miles wide. The range is easily accessible by use of the paved Painted Rock Road which crosses the historic Butterfield Stage Route (once the Gila Trail and the route followed by the Mormon Battalion in 1846), and extends northward to Painted Rock Dam. The study area encompasses parts of the following 1:24,000 scale U.S. Geological Survey topographic maps: Citrus Valley West, Theba, Dendora Valley, and Sentinel NE. Bedrock consists mostly of Miocene intermediate to felsic volcanic rock that has been intruded by a granitic pluton and is overlain by basalt (plate 1; Fig. 2). Field work during February and March, 1993, coincided with filling of the Painted Rock Reservoir to peak capacity and overflow of the spillway (the first time since the dam was constructed). The high water level is marked on Plate 1. The nomenclature for the rock descriptions was adopted and modified from both the U.S. Army Corps of Engineers Painted Rock Dam 1987 Red Book report and U.S. Geological Survey Open-File Report 87-347. This project was jointly funded by the Arizona Geological Survey and the U.S. Geological Survey COGEOMAP program, contract #1434-92-A-1061.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