Age of volcanism, intrusion, and mineralization in the Thomas Range, Keg Mountain, and Desert Mountain, western Utah
Links
- Document: Report (20.87 MB pdf)
- Download citation as: RIS | Dublin Core
Abstract
Twenty-six new age determinations by the fission-track method establish a chronology for volcanism, intrusion, and mineralization in the Thomas Range, Keg Mountain, and Desert Mountain, in western Utah. The fission-track ages confirm D. R. Shawe's three-fold classification of igneous rocks. The oldest group of rocks consists of flows, agglomerates, and some ash-flow tuffs that were deposited 38-39 m.y. ago. The middle group contains widespread rhyolitic ash-flow tuffs that originated from local volcanic centers 30-32 m.y. ago. A dike emplaced along the probable ring-fracture zone of the Keg caldera about 31 m.y. ago indicates that caldera collapse occurred soon after eruption of ash-flow tuffs. Rocks believed to belong-to the middle group also were intruded by the quartz monzonite of Desert Mountain 27-30 m.y. ago. Little or no igneous activity took place within the next 20 m.y., during which time the region was strongly broken by Basin-and-Range faulting. Rhyolites of the youngest group were extruded 8-10 m.y. ago in the Keg Mountain area and 6-7 m.y. ago in the Thomas Range. The beryllium-fluorite mineralization at Spor Mountain occurred after the rhyolitic volcanism in the Thomas Range.
Suggested Citation
Lindsey, D.A., Naeser, C.W., Shawe, D., 1975, Age of volcanism, intrusion, and mineralization in the Thomas Range, Keg Mountain, and Desert Mountain, western Utah: Journal of Research of the U.S. Geological Survey, v. 3, no. 5, p. 597-604.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Age of volcanism, intrusion, and mineralization in the Thomas Range, Keg Mountain, and Desert Mountain, western Utah |
| Series title | Journal of Research of the U.S. Geological Survey |
| Volume | 3 |
| Issue | 5 |
| Year Published | 1975 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Publisher location | Reston, VA |
| Description | 8 p. |
| First page | 597 |
| Last page | 604 |
| Country | United States |
| State | Utah |
| Other Geospatial | Thomas Range, Keg Mountain, Desert Mountain |
| Online Only (Y/N) | N |
| Additional Online Files (Y/N) | N |