Multiple episodes of hydrothermal activity and epithermal mineralization in the southwestern Nevada volcanic field and their relations to magmatic activity, volcanism and regional extension
Volcanic rocks of middle Miocene age and underlying pre-Mesozoic sedimentary rocks host widely distributed zones of hydrothermal alteration and epithermal precious metal, fluorite and mercury deposits within and peripheral to major volcanic and intrusive centers of the southwestern Nevada volcanic field (SWNVF) in southern Nevada, near the southwestern margin of the Great Basin of the western United States. Radiometric ages indicate that episodes of hydrothermal activity mainly coincided with and closely followed major magmatic pulses during the development of the field and together spanned more than 4.5 m.y. Rocks of the SWNVF consist largely of rhyolitic ash-flow sheets and intercalated silicic lava domes, flows and near-vent pyroclastic deposits erupted between 15.2 and 10 Ma from vent areas in the vicinity of the Timber Mountain calderas, and between about 9.5 and 7 Ma from the outlying Black Mountain and Stonewall Mountain centers. Three magmatic stages can be recognized: the main magmatic stage, Mountain magmatic stage (11.7 to 10.0 Ma), and the late magmatic stage (9.4 to 7.5 Ma).
- Publication Date:
- OSTI Identifier:
- Report Number(s):
ON: DE96006638; TRN: 96:013589
- Resource Type:
- Technical Report
- Resource Relation:
- Other Information: PBD: 1994; Related Information: Is Part Of Evaluation of the geologic relations and seismotectonic stability of the Yucca Mountain Area Nevada Waste Site Investigation (NNWSI). Progress report, 30 September 1994; PB: 350 p.
- Research Org:
- Nevada Univ., Reno, NV (United States). Center for Neotectonic Studies
- Country of Publication:
- United States
- 05 NUCLEAR FUELS; 58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; HIGH-LEVEL RADIOACTIVE WASTES; UNDERGROUND DISPOSAL; NEVADA; VOLCANISM; MINERALS; HYDROTHERMAL ALTERATION; YUCCA MOUNTAIN; SITE CHARACTERIZATION; CALDERAS; FLUORITE; LAVA; MINERALIZATION; SEDIMENTARY ROCKS; VOLCANIC ROCKS; TUFF; GEOLOGIC FAULTS; ISOTOPE DATING; PROGRESS REPORT
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