PLIOCENE FAULTING IN EASTERN QUEEN VALLEY, NEVADA; IMPLICATIONS FOR STRAIN TRANSFER IN THE CENTRAL WALKER LANE BELT

The central portion of the Walker Lane belt, known as the Mina deflection, is characterized by several large pull-apart structures that are structurally controlled by NE-trending normal faults that transfer slip from the southern to the northern Walker Lane belt. One of these pull-apart structures is located in Queen Valley at the northern termination of the right-lateral Owens Valley/White Mountains fault system. Previous structural and thermochronological studies have documented the inception of extensional faulting in the Queen Valley pull-apart basin at ~3 Ma. This study presents new mapping, geochronological and geochemical data investigating the structural transfer of late Cenozoic displacement eastward into the Mina deflection. Detailed mapping in progress shows that a significant portion of strain is being transferred eastward out of eastern Queen Valley onto the E-W trending left-lateral Coaldale fault in different domains and in distinctly different structural styles. The northern margin of Queen Valley is characterized by several ENE-trending left-lateral fault zone with a minimum of ~1 km of Pliocene displacement, based on offset ~3 Ma basalt. These faults feather out westward into northern Queen Valley where they are expressed as a series of Holocene fault scarps within the basin floor. Eastward several of these faults merge with the Coaldale fault in the Montgomery Pass area. Along the southeastern margin of the pull-apart structure, the curvilinear Queen Valley normal fault swings into a N-S orientation while progressively transferring displacement eastward into the footwall block along several major NE-trending relay normal faults. The nature of the kinematic interaction of these normal faults with the Coaldale fault is still under investigation. The abundance of pre-, syn-, and post-tectonic bimodal volcanism in the area allows for a detailed reconstruction of faulting and volcanism. Samples are currently being analyzed using major and trace-element geochemistry and geochronology to resolve the timing of volcanism and faulting and to evaluate the kinematics of eastward strain transfer out of Queen Valley. The goal of this study is the quantification of the magnitude of displacement that is transferred eastward to the Coaldale fault as well as the amount distributed more diffusely northward.