THE ROLE OF NORMAL AND STRIKE-SLIP FAULT INTERACTION IN THE SEGMENTATION OF THE BASIN AND RANGE PROVINCE: AN EXAMPLE FROM THE QUATERNARY-ACTIVE KANE SPRINGS WASH FAULT ZONE, NEVADA, USA

Different extensional magnitudes and styles between the northern and central Basin and Range subprovinces require a zone of transverse structures to accommodate that difference and through which fault slip and strain can be transferred between the two subprovinces. Geodetic data show that the boundary zone between the northern and central subprovinces coincides with a zone of concentrated transverse left-lateral deformation that has a strain rate of 1.8 mm/yr compared to 0.9 and 1.1 mm/yr of diffuse E-W extension north and south of it, respectively. However, the geometric, kinematic and mechanical characteristics of the transverse deformation and how strain and slip are transferred between the north and south are still enigmatic. To address this issue, we focused on an example of interactions between extensional and strike-slip deformation that takes place along the boundary zone that is provided by three ~20-65 km long Quaternary faults located along the southern margin of the boundary zone: The N-striking normal Coyote Spring fault (CSF); ENE-striking left-lateral Kane Springs Wash fault (KSWF); and N-striking normal Wildcat Wash fault (WWF), from N to S. We used standard field mapping at 1:12,000 scale and satellite image analysis to document the relative ages, structural geometries, and magnitudes of deformation in the interaction zone. The interactions among these faults occurs through several processes. The CSF splays into two faults and curves SE as it propagated toward and merged with the KSWF. In contrast, pre-existing NE-striking fractures of the KSWF off-fault process zone hindered the northward propagation of the WWF by means of crack-tip shielding. Instead, the WWF curves NE and grows by linking to the KSWF. Both linkage zones allow slip transfer between the faults. The long-term southwestward propagation of the KSWF between the CSF and WWF can be facilitated by fractures in an off-fault process zone. Together, the fault linkage geometries and spatial distribution suggest that the KSWF allows slip transfer between the CSF and WWF. These relations suggest that the slip transfer between the central Basin and Range and the boundary zone with the northern subprovince takes place along hard-linked normal and left-lateral fault networks that, together, contribute to the segmentation of the Basin and Range rift