Eventual solution to the problems of gold ore trends localization in the Carlin province (Nevada, USA)

Abstract

Multi-year research on Carlin-type noble-metal mineralization has allowed the determination of deposit distribution trends, as well as the identification of several stratigraphic, geological-structural, and physicochemical conditions for the formation of the deposits. However, empirical conclusions do not fully encompass the results of modern geophysical and seismotomographic investigations. The involvement of the latter in the determination of the formation and distribution characteristics of known trends enables us to acknowledge that the Carlin world-class gold-ore province (Nevada, USA) is situated in the rear zone of the marginal-continental volcanic-plutonic belt with late Mesozoic–Cenozoic magmatism manifestations and linear belts of endogenous deposits of different formational and mineral types, which are diffusely scattered across the area of accretionary orogens. The formation of late Mesozoic–Cenozoic ore-magmatic systems in the province is predetermined by retinues of underslab and overslab asthenospheres that have been positioned as two layers beneath the continental lithosphere. The lower asthenosphere located in the mantle transition zone under the subducted Farallon plate contacted the higher asthenosphere by the upwelling of toroidal and poloidal fluid-energetic flows. Known trends of Carlin-type Au deposits were controlled by two permeable structures of deep-level geodynamics: the sublatitudinal structure of the Mendocino transform-type fault zone (Getchell and Jerritt Canyon trends), which bounds the Farallon plate in the north, and the paleo-spreading center of the East Pacific Rise of a NNW strike (Battle Mountain Eureka, Carlin, and Alligator Ridge trends).