ARIZONA

The Black Canyon country of central Arizona lies in the Central Highlands physiographic province of Arizona. The Central Highlands Province is a northwest-southeast trending belt of uplifted rock that forms a transition zone between the stable platform deposits of the Colorado Plateau to the north and the desert mountains of the Basin and Range Province to the south. This tectonically-active belt has undergone several episodes of folding, faulting, and uplift. Uplift has been quite dramatic. In fact, so dramatic that the thick blanket of Paleozoic and Mesozoic sedimentary rocks that once rested upon the ancient Precambrian core has been completely stripped away by erosion. Consequently, many mountain ranges in the Central Highlands Province consist of an exposed

core of Precambrian igneous and metamorphic rocks. The Bradshaw Mountains are such a range. The Bradshaws consist almost entirely of ancient Precambrian schist intruded by slightly younger Precambrian granitic rocks. These ancient, dark-colored schists are some of the oldest rocks in Arizona and form the basement rock into which the younger granites intrude. The Black Canyon cuts through these ancient schists and takes its name from them.

Placer gold has been recovered in varying amounts in nearly every tributary of Black Canyon Creek and in the main stream itself. Turkey Creek, Poland Creek, and Arrastre Creek were all minor but steady producers. Prospectors may want to

concentrate on the Black Canyon gravels, in particular those lying between Arrastre Creek and Poland Creek. Gravel bars and stream terraces in this area may prove to be locally rich. In this case, a metal-detector may be useful in the search.