Geology, mineralization, and alteration of the Jhus Canyon area, Cochise County, Arizona

Abstract

The Jhus Canyon area, located on the northeastern flank of the Chiricahua Mountains, Cochise County, Arizona, contains rock units from Precambrian to Mid-Tertiary in age. Precambrian granite, Paleozoic and Early Cretaceous sedimentary rocks, and Late Cretaceous(?) andesitic lava flows have been intruded by a complex Mid-Tertiary stock. The youngest rocks present are Mid-to-Late Tertiary rhyolite dikes. The effects of hydrothermal alteration are conspicuous both within and adjacent to the stock. The igneous rocks of the stock display propylitic, argillic, and phyllic alteration. Sedimentary hosts were altered to skarn, hornfels, and marble. Silicification is prominent in both the igneous and sedimentary rock types. Pyrite is the most abundant sulfide mineral in the area, but minor amounts of chalcopyrite and molybdenite are also present. The existing level of erosion is believed to expose the most intense and extensive alteration and mineralization that developed. No ore deposit is thought to exist here, but molybdenum values from rock chip samples suggest that the southwestern lobe of the stock is worthy of closer examination, especially for skarn occurrences. Mineralization in the nearby Hilltop Mine area is not related to the Jhus Canyon Stock, and its ore potential must be evaluated independently.