Abstract

We propose a genetic relationship between the 43–34 Ma magmatism, extensional tectonics, and gold mineralization event centered in the Great Basin of Nevada and the development of the ancestral Yellowstone hotspot. The model is compatible with Cenozoic regional tectonics and provides a plausible explanation of the spatial coincidence of the Eocene-Oligocene magmatic events and the Carlin-type gold deposits. These features are centered in the Battle Mountain region of the Great Basin, coincident with the inferred ca. 40–30 Ma position of the Yellowstone hotspot.

The Yellowstone hotspot is probably a plume that ascended from the core-mantle boundary, a region thought to be anomalously rich in gold and in the moderately siderophile elements associated with gold deposits. As the hotspot was progressively overridden by the North American plate after ca. 60 Ma, a magmatically quiescent period related to subhorizontal subduction gave way to the generation of ca. 43–34 Ma voluminous intracrustal melts and metamorphic devolatization as the hotspot broke though the subducted Farallon plate. Coeval crustal extension and convective circulation of hydrothermal fluids in the upper crust facilitated the exploitation of the structural and lithologic traps that characterize the classic Carlin-type deposits.

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