Reference 1086
Miller, David M; Nakata, John K; Glick, Linda L (1990) U. S. Geological Survey Bulletin, Report: B 1906, 18 pp., 1990
| Authors | Miller, David M; Nakata, John K; Glick, Linda L |
|---|---|
| Year | 1990 |
| Source | U. S. Geological Survey Bulletin, Report: B 1906, 18 pp., 1990 |
| ISSN | 8755-531X |
| GeoRef | 1990-052600 |
| Keywords | absolute age; age; biotite; Box Elder County Utah; Cenozoic; cooling;Cretaceous; dates; dikes; Elko County Nevada; emplacement; Eocene;evolution; geochronology; igneous rocks; intrusions; Jurassic; K/Ar;Mesozoic; metamorphic rocks; metamorphism; mica group; muscovite;Nevada; Newfoundland Mountains; northeastern Nevada; northwesternUtah; Paleogene; plutonic rocks; plutons; sericite; sheet silicates;silicates; Silver Island Mountains; Tertiary; thermal history; ToanoRange; United States; Upper Cretaceous; upper Eocene; Upper Jurassic;USGS; Utah |
Abstract
Five granitoid plutons in the Newfoundland Mountains, Silver IslandMountains, and Toano Range yielded Late Jurassic 155- to 150-Ma,Late Cretaceous 77-Ma, and late Eocene 37-Ma K-Ar ages. Thesecooling ages somewhat postdate the times of pluton emplacement, butthey correspond closely to other K-Ar ages for plutons in the regionsuggesting that these ages approximate the times for regionwide pulsesof plutonism. Metamorphic rocks in the Toano Range yielded a scatterof K-Ar mica ages from 94 to 61 Ma that is interpreted as variableresetting of ages by a thermal event caused by nearby Late Cretaceousplutonism followed by prolonged cooling. In contrast, metamorphicmica from the western Raft River Mountains yielded a Tertiary 30-MaK-Ar age that corresponds well to previous dating of the metamorphismin that metamorphic core complex.