Tectonic Evolution of the Southern Walker Lane Belt: New Paleomagnetic Constraints From the Mina Deflection, California–Nevada

Abstract

Paleomagnetic data from 269 Pliocene basalt flow sites and 10 sites in the Candelaria Junction Tuff constrain Pliocene vertical‐axis rotation from Mono Lake, California to the Marietta Salt Marsh, Nevada. Our data refine efforts to track strain transfer from the Garlock Fault northward through Owens Valley, the Mina Deflection, and into the Walker Lane Belt (WLB). Rotation estimates from basalts and the Candelaria Junction Tuff reveal spatially variable vertical‐axis rotations consistent with patterns observed west, east, and north of the study area. The new data record both clockwise and counterclockwise rotations among individual structural crustal blocks, supporting a modified simple‐shear model in which sinistral‐normal slip and block rotation operate within a distributed shear couple between the Eastern California Shear Zone and the WLB. Newly identified rotations in the Adobe Hills and southern Huntoon Valley area extend the known footprint of Pliocene deformation to the eastern shore of Mono Lake. As the Sierra Nevada block translates northwestward, the Mina Deflection accommodates strain through block rotation, fault interaction, and localized extensional basin formation. The paleomagnetic constraints presented here add key temporal and kinematic insight into this evolving plate‐boundary hinge and provide foundational data for future efforts to better constrain and refine aspects of displacement transfer models for the region.