COMPLEX PATTERNS OF NEOTECONIC TRANSLATIONAL AND CONTRACTUAL STRAIN WITHIN THE SOUTHERN DEATH VALLEY AREA RELATVE TO REGIONAL DEFORMATION PATTERNS IN THE EASTERN CALIFORNIA SHEAR ZONE

Detailed regional surficial mapping indicates that neotectonic (post 4 Ma) deformation in the southern Death Valley (SDV) region comprises spatially varying patterns of transcurrent and contractional surface strain related to positon within the Eastern California Shear Zone (ECSZ). Neotectonic strain in the SDV area is dominated by sets of strike-slip faults with differing orientations and structural styles that complexly interact with one another. These include NW-oriented dextral strike-slip faults within and adjacent to southern Death Valley basin including the southern Death Valley (SDVf) and southern Panamint Valley (SPVf) faults. To the southeast, these structures intersect, abut against, and (or) merge with--but do not cross or displace--the east end of the sinistral E-trending Garlock fault (EGf). This major fault traverses eastward across basins and highlands to the south of the SDV system and forms the northern structural boundary of a regional domain of similarly oriented, E-trending sinistral faults in terrain to the south. The resulting regional strain field comprises both large translations along major strike-slip fault systems and widespread contraction, evidenced in blind thrust faults and folds as well as areas of major downwarping, tilting, and uplift (e.g., NE Avawatz Mountains). These strain indicators increase in degree of development and complexity in and adjacent to zones where the two contrasting fault domains intersect. Most of the small to intermediate-scale contractional features are related to a combination of: (a) transpressive strain along the regional transcurrent faults; (b) on- and off-fault deformation near the intersection zones between two or more faults; and (or) (c) internal deformation, vertical displacement, and local lateral extrusion of crustal blocks (e.g., the Owlshead Mountains) along bounding sets of intersecting faults. The orientation, geometry, and kinematics of the EGf is greatly impacted by intersections with dextral faults from the NW, which incrementally induce (a) a SE deflection of the fault, and (b) eastward increases in the width, number, geometric complexity, and amount of tranpression along internal strands of the fault. These changes reflect the major structural role of this transversely oriented, domain-bounding structure in the ECSZ.