GSA Connects 2021 in Portland, Oregon

Paper No. 195-7
Presentation Time: 2:30 PM-6:30 PM


AMAYA LOPEZ, David, HAISLER, Jason, MORRISON, Max, PREECE, Camille, RANDALL, Allyson, RUANGSAK, Thae, SILVER, Ryan and LOBIANCO, Samuel, Department of Earth Science, University of California, Santa Barbara, Santa Barbara, CA 93106

In the central Egan Range of White Pine County, NV, Huesser Mountain consists of the Ediacaran McCoy Creek Group and Cambrian carbonates intruded by Eocene granite. These units are offset by Eocene and Miocene extensional fault systems. Previous studies mapped the McCoy Creek Group with lithostratigraphic units from the adjacent Schell Creek Range; however, local facies variations have prohibited regional correlations of the McCoy Creek Group across White Pine County in a tectonostratigraphic context. Our new mapping details the extent of the cross-cutting Eocene and Miocene normal fault systems and constrains the relative timing of Eocene magmatism and extension at Huesser Mountain. Furthermore, our newly defined Huesser Mountain Formation serves as the basis for a new sequence stratigraphic definition of the lower McCoy Creek Group stratigraphy, beginning with the earliest Ediacaran post-Snowball Earth transgression. The upper McCoy Creek Group records Ediacaran reactivation of rifting on the western margin of Laurentia in a slope environment. Fine clastic slope sedimentation is interrupted by sandstone and conglomerate channel deposits interpreted to record intervals of relative sea-level fall. This stratigraphic motif culminates with the sub-Cambrian unconformity and fluvial deposition of the Prospect Mountain Quartzite.