Geologic map of the Picture Rock Hills quadrangle, Juab County, Utah (MP 99-3)

By: M. A. Shubat

The Picture Rock Hills 7.5 minute quadrangle is in west-central Utah and encompasses the Picture Rock Hills and the southwestern part of Keg Mountain. Keg Mountain and the Picture Rock Hills are part of a large, late Eocene to early Oligocene igneous center that spans the Thomas Range, Keg Mountain, and northern Drum Mountains. Consequently, the quadrangle is underlain by volcanic and intrusive rocks, and several calderas and cauldrons are in or near the quadrangle. The Eocene and Oligocene ash-flow tuff units in the quadrangle are, in chronological order, the Keg Tuff, Mt. Laird Tuff, and Joy Tuff. Intrusive rocks are present in the quadrangle that are probably co-magmatic with the Keg and Joy Tuffs. Flows, domes, and intrusions of Miocene Topaz Mountain Rhyolite unconformably overlie and intrude the older volcanic rocks. Deposition of sediments during Quaternary time was dominated by Lake Bonneville, which covered most of the quadrangle. Other surficial deposits include stream alluvium, colluvium, and alluvial-fan and eolian deposits. Potential mineral resources in the quadrangle include base and precious metals, uranium, sand and gravel, zeolite minerals, crushed stone, and dimension stone

Other Information:
Published: 2000
Pages: 22 p.
Plates: 2 pl.
Scale: 1:24,000
Location: Juab County
Media Type: Paper Map