The geology and ore deposits of the Antelope (Majuba Hill) mining district, Pershing County, Nevada
Authors
Stevens, David Lee
Issue Date
1971
Type
Thesis
Language
en_US
Keywords
Antelope Mining District , Majuba Hill| Mine , Copper , Tin Mineralization , Sedimentary Rocks , Argillites , Quartzites , Grass Valley Formation , Early Cretaceous Compressional Deformation , Thrusting , Emplacement Of Igneous Rocks , Large Concordant Intrusions , Sill Swarms , Explosive Vents , Magma Columns , Quartz , Sericite , Tourmaline , High Temperature Ore , Gangue Minerals , Xenothermal , Bolivia , Pershing County , Nevada , Mackay Theses and Dissertations Grant Collection
Alternative Title
Abstract
The Antelope (Majuba Hill) mining district is credited with 1.6 million dollars of production between 1905 and 1936. The Majuba Hill mine, in the center of the district, was the major producer with nearly 3 million pounds of copper. The presence of tin mineralization in the Majuba Hill mine makes the district anomalous among mining districts in the western United States. Sedimentary rocks of the district consist of argillites and quartzites of the Triassic "Grass Valley Formation". Early Cretaceous compressional deformation, and perhaps thrusting, produced the northeasterly trending fabric of the beds and folds. Emplacement of intermediate igneous rocks as large concordant intrusions and sill swarms during the mid-Cretaceous followed the main stage of deformation. During the Tertiary, a large explosive vent developed in response to violent volatile release from a buried magma chamber. Following volatile release, the upper siliceous portions of the magma chamber ascended the explosive vent. Upon reaching the surface, the viscous rhyolite magma welled into a large fan shaped extrusive dome. Sulfide mineralization in the throat of the vent was localized in a tensional fault produced by subsidence of the magma column. Mineralization in the district, outside of the Majuba Hill plug, appears unrelated to the rhyolite intrusion and may represent an earlier hydrothermal phase from the same parent magma.
The interior of the Majuba Hill rhyolite plug is intensely altered to quartz, sericite, and tourmaline. Alteration is most intense where localized in intrusive breccias. The presence of high temperature ore and gangue minerals in a low pressure, near surface environment classifies the mineralization associated with the Majuba Hill plug as xenothermal. Mineralogically and genetically the Antelope mining district has many similarities with the tin districts of central Bolivia.
Description
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Citation
Publisher
University of Nevada, Reno
License
In Copyright(All Rights Reserved)