Arizona Geological Survey
Map of Arizona geologic hazards
New geologic mapping from the Cedar Mountains - Bloody Basin - Cooks Mesa area in the central Arizona Transition Zone presents an enigmatic geologic relationship that has previously gone unstudied. Here, fault blocks of Early Proterozoic basement overlain by Tertiary sedimentary and tuffaceous-lacustrine deposits and capped by a thick accumulation of basalt flows, dated in the project area between 15.1 and 13.5 Ma, are rotated ~20o west to west-southwest along east-dipping normal faults.
The Copper Mountain quadrangle is centered just north of the southwest-facing escarpment on the southwest side of the crest of the Sierra Ancha. Elevations range from about 4200 feet in the southwest corner of the map to 6676 feet at Copper Mountain.
This report is a compilation of available data on Quaternary faults in Arizona as of the summer of 1998. These data were compiled as part of a effort to compile data and map information on Quaternary faults throughout the world, which is being overseen by Michael Machette of the U.S. Geological Survey.
This geologic map was produced to compile and reinterpret published geologic information, and present the result of new geologic mapping in the Ray-Superior area. This data set serves as the basis for ongoing efforts to better understand the geologic history of this area, particularly with respect to the distribution and origin of mineral deposits.
The study area is situated along the southern edge of the Superstition Mountains approximately 40 miles east of the greater Phoenix metropolitan area (Figure 1). Geology is dominated by mid-Tertiary volcanic rocks of the Superior volcanic field (Ransome, 1903), and these rocks depostionally overlie a crystalline basement of early Proterozoic Pinal Schist intruded by middle Proterozoic granitoids. In some areas a relatively thin sequence of the Middle Proterozoic Apache Group occurs along the contact between these two rock types.
Geologic map, black and white
