Plate-boundary transverse deformation zones and their structural roles in localizing mineralization in the Virginia City, Goldfield, and Silver Star mining districts, Nevada

Subduction-boundary zones are structurally complex. Nevertheless, each zone
may be generalized into segments and structural domains, each domain displaying
different deformation styles. Fault zones within domains or along domain boundaries
oriented at high angles or transverse to major orogenic boundaries have long been
recognized as having some role in the localization of ore deposits, but the structural
nature and importance of such fault zones to ore genesis have received limited
detailed attention. From the analysis of geophysical and geologic data, we propose
that in the Virginia City and Goldfield mining districts, Nevada, east-west transverse
faults accommodated little displacement, yet perturbed the local strain field and
thereby played important roles in the structural localization of mineralization-related
magmatic activity as well as in the localization of ore bodies within the mineralizing
systems. In contrast, in the Silver Star mining district (eastern Excelsior Mountains),
Nevada, transverse faults accommodated significant displacement and, along with
kinematically linked normal faults, served to localize magmatism and hydrothermal
activity and related ore. The different roles played by transverse faults have implications
for minerals exploration, probable ore-reserve estimation, and the estimation of
undiscovered mineral-resource potential in permissive terranes.