KINEMATIC ANALYSIS OF THE SOUTHERN FUNERAL MOUNTAINS, INYO COUNTY, CALIFORNIA: MAGNITUDE OF TERTIARY EXTENSION AND PALEOZOIC SHORTENING

Cornerstone palinspastic reconstructions of Cordilleran thrust surfaces in the central Basin and Range have only included surface relationships and do not incorporate the detailed interactions between compressional and extensional structures in the Funeral Mountains, Inyo County, California. Estimates for the magnitude of strike slip displacement on the Death Valley-Furnace Creek Fault Zone (DV-FCFZ) are based on the correlation of two sets of three compressional structures in the Funeral and Cottonwood Mountains. These correlations are substantiated because the pattern of size, order, spacing, and vergence is statistically unlikely to be random. The spacing used for this palinspastic reconstruction is derived from present-day map-view positioning. Upon closer look, Tertiary extension has separated these ‘piercing points’ from their true pre-extensional spacing.

A balanced and restored structural cross section through the Funeral Mountains reveals that the magnitude of extension within this stable range block is approximately 25%. The NW-directed extension has separated the Clery thrust from the Schwaub Peak thrust, making them less viable for structural correlations. If the compressional structures in the Cottonwood Mountains and Funeral Mountains are not correlative, then the magnitude of strike slip displacement across the DV-FCFZ may need to be re-evaluated, and other palinspastic reconstructions using similar methods may not be valid.