Award Date
1-1-2000
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Geoscience
First Committee Member
Jean S. Cline
Number of Pages
148
Abstract
Samples of banded veins, microcrystalline quartz veins, and hydrothermal breccias +/- Au in the southern Castle Mountains, California were collected from four different zones within and up to 5 km outside the mine area in order to construct a paragenesis, interpret fluid origin, describe the thermal history, and examine fluid inclusion gas compositions as an exploration tool for low-sulfidation deposits. Two-thirds of the gold from the Lesley Ann deposit is associated with pyrite, found in zones of intense silicification, and precipitated due to sulfidation of rhyolitic host rock during the earliest stages of hydrothermal activity. The remaining gold occurs freely in breccia matrix quartz and was deposited after silicification as a result of cooling and boiling of 200 to 240°C fluids with 0 to 0.2 wt % NaCl equivalent. Late banded quartz and drusy quartz precipitated in all areas from 150 to 185°C waters with 0 to 1.1 eq wt % NaCl equivalent. Chalcedony bands adjacent to quartz in barren banded veins north of the mine area represent temperature drops likely resulting from abrupt changes in boiling zone levels, evidenced by platy calcite textures found in a few, but not all, quartz bands. (Abstract shortened by UMI.).
Keywords
California; Epithermal; Fluid; Gold; History; Low; Origin; Paragenesis; Silver; Sulfidation; Systems; Thermal
Controlled Subject
Geology; Municipal engineering; Sanitary engineering; Chemistry, Analytic; Geochemistry
File Format
File Size
4249.6 KB
Degree Grantor
University of Nevada, Las Vegas
Language
English
Permissions
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Repository Citation
Rotert, Joel William, "Paragenesis, fluid origin, and thermal history of a low-sulfidation epithermal gold-silver system" (2000). UNLV Retrospective Theses & Dissertations. 1223.
http://dx.doi.org/10.25669/b81b-806t
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