Geology of the Southern Stansbury Range, Tooele County, Utah

The Stansbury Mountains consist of a single north-south trend­ing range located west of Tooele, Utah. Approximately 70 square miles of the southern Stansbury Mountains were mapped and studied for this report. A section of Paleozoic rocks, in excess of 27,000 feet is present. This includes 4,800+ feet of Cambrian (not includ­ing several thousand feet of unmeasured Tintic quartzite), 1,600+ feet of Ordovician, 600+ feet of Silurian, 600+ feet of Devonian, 3,400+feet of Mississippian (not including 1,200+ feet of unmeasur­ed Manning Canyon shale), and 14,000+feet of Pennsylvanian. Due to a pre-Mississippian uplift, Ordovician, Silurian, and Devonian rocks are absent in the central part of the range. The basal Mississippian rocks rest unconformably on Cambrian beds. Late Devonian beds, where present, are represented by a coarse conglomerate referred to as the Stansbury conglomerate. This formation which is hundreds of feet thick at the north end of the range, thins to a few tens of feet at the south end. Precambrian, Mesozozic and Tertiary rocks are not exposed in the area studied. Quaternary deposits includes pre-Lake Bonneville fan gravels, Lake Bonneville beds, creep and glacial deposits, Recent sand dune deposits and alluvium. Structurally the range consists of a north-south anticline. At the south end following folding., the west limb was removed by Laramide thrusting. Also during the Laramide period, high angle northwest- southeast normal faulting occurred. Later Basin and Range normal type faults roughly parallel the Laramide faults and fold structures.