Geologic Deformation of the Eastern Flank of the Horse and Northern Grant Ranges, NV

Event Center A&B

Previous theories regarding deformation patterns in the Horse and northern Grant Ranges proposed minimal deformation before Cenozoic time. New data provided evidence that constructional deformation occurred during Cretaceous time and the data also provided insight into a more structurally complex pattern of folded and tilted rocks prior to extensional events. Analysis of a cross section and reconstruction to remove extensional deformation events showed a major thrust fault folded the Paleozoic and Cenozoic formations in the hanging wall and folded the Paleozoic formations in the footwall. Geometries of the reconstruction indicated that further examination to the south and east may tie this event into the Sevier orogeny. Reconstructions of the event also provided evidence that a major normal fault with a minimal plausible slip of 22,516 feet (6.9 kilometers) fractured through the thrust fault during Cenozoic time and overturned the units in the hanging wall of this thrust fault.