The Big Sandy Valley is located in Mohave County, northwestern Arizona, and lies between the Hualapai Mountains to the west and the Aquarius Mountains to the east. In Fall 2020, the Arizona Geological Survey began a multi-year mapping campaign starting with the Gunsight, Aubrey Peak (formerly Wikieup NW), Tule Wash, Wikieup, and northern half of the Greenwood Peak 7.5’ quadrangles. Most of the Aquarius and Hualapai Mountains consists of Paleoproterozoic metasedimentary and granitic gneisses, locally intruded by Mesoproterozoic igneous rocks. In the southern Hualapai Mountains, the older rocks are intruded by two late Cretaceous plutons, with several spatially extensive dike swarms. The two plutons, and at least some of the dikes, are associated with weakly-developed hydrothermal alteration and mineralization interpreted to be related to a porphyry copper system. A diverse assemblage of Miocene volcanic rocks are present in the Wikieup quadrangle. The basin itself hosts two sets of basin deposits in the Tule Wash formation and the Big Sandy Formation. Both formations have diverse and variable lithofacies, with the Tule Wash formation (defined in the Tule Wash quadrangle) generally moderately tilted and faulted, while the Big Sandy Formation is typically undeformed. River, tributary, and fan deposits record the history of basin filling and subsequent dissection due to integration into the larger Bill Williams River watershed.Documents in the AZGS Documents 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 [email protected]
