Provisional geologic map of the Levan quadrangle, Juab County, Utah (M-135)

By: W. L. Auby The Levan quadrangle is located along the northwestern part of the Gunnison Plateau. Rocks mapped range from Jurassic marine sediments to Quaternary surficial deposits. The Jurassic Arapien Shale is the most extensive unit mapped and, despite its name, is composed largely of thin-bedded to laminated micrite. Terrestrial Cretaceous strata were deposited in a thick, coarse clastic wedge adjacent to the Sevier orogen. Latest Cretaceous and early Tertiary strata were deposited in a foreland basin between the Sevier orogenic belt and the Laramide uplifts farther east. Depositional settings at that time progressed from alluvial to lacustrine. Volcanism occurred in the Oligocene and Miocene and is represented by volcaniclastic sediments and igneous intrusives. Monzonite intrusives yield a radiometric age of approximately 23.4 Ma. The Pleistocene is represented by large mass-movement deposits. Preliminary mapping, which included the Levan quadrangle, was first conducted by Hunt