Structural and Geochemical Analyses of Disseminated-Gold Deposits, Bald Mountain-Alligator Ridge District, Nevada: Insights into Fault-Zone Architecture and Its Effect on Mineralization

Structural and geochemical analyses of the Top and Casino deposits, Bald Mountain-Alligator Ridge district, Nevada, were conducted to determine how structures affected gold deposition in Carlin-type deposit s. We also examined how permeability changed over time in a fault that cuts siltstone-dominat...

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Bibliographic Details
Main Author: Hammond, K. Jill
Format: Others
Published: DigitalCommons@USU 2001
Subjects:
Online Access:https://digitalcommons.usu.edu/etd/6719
https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=7784&context=etd
Description
Summary:Structural and geochemical analyses of the Top and Casino deposits, Bald Mountain-Alligator Ridge district, Nevada, were conducted to determine how structures affected gold deposition in Carlin-type deposit s. We also examined how permeability changed over time in a fault that cuts siltstone-dominated sedimentary rocks. The association of gold and related arsenic with faults at the margins of a Jurassic pluton and sedimentary rocks suggests that ore fluids migrated along faults and fracture s. Permeability of the faults changed over time within the Casino deposit, where the ore-controlling fault was a distributed conduit in the early stages of mineralization but a barrier and a localized conduit a t opposite ends of the deposit during later stages. Results indicate that faults may significantly influence patterns of ore deposition and change character over deposit-scale distances, and continued slip along faults may create clay-rich low-permeability faults that are mineralized during early stages of development.