Geology of the Virgin and Beaverdam Mountains, Arizona

The Virgin and Beaverdam Mountains form an arcuate range in northwestern Mohave County, Arizona, which extends northeasterly from the Nevada State line and swings to a northerly trend near the Utah boundary. The range lies on the eastern edge of the Basin-and-Range province, adjacent to the Plateau province, and has a maximum topographic relief of nearly 6,500 feet. Rocks ranging in age from Precambrian to Tertiary are exposed in the Virgin and Beaverdam Mountains. Precambrian rocks consist of a metamorphic and igneous complex. The Paleozoic Era is represented by marine carbonate rocks with subordinate, fine-grained clastic material. Mesozoic and Cenozoic rocks are for the most part clastic units of continental origin. Structural elements that have played a major part in the development of the range include a large anticlinal fold and a zone of reverse faulting that extends for nearly 20 miles along the eastern flank of the range. The basic pattern established by these structures has been modified by highangle faults of large displacement which strike substantially parallel with the line of reverse faulting, and by transverse faults of less displacement. In the northern part of the range low-angle thrust faulting is locally prominent. 65 p.