NEW INSIGHTS INTO THE BACK-ARC BASIN EVOLUTION OF THE NORTH AMERICAN CORDILLERA: PRELIMINARY OBSERVATIONS FROM NORTHWEST NEVADA

Understanding back-arc basins challenge geoscientists because back-arcs are prone to mechanical weakening and strain localization that makes them susceptible to future deformation and destruction in response to kinematic changes between the overriding plate and downgoing slab. As a result of rapid tectonic changes, constraining the timing and rate of sedimentation, subsequent shortening, and closure can be challenging. Research on the back-arc of the Mesozoic North American Cordillera can inform us about the broad evolution of the Cordillera and its response to plate-tectonic boundary interactions. The Cordilleran back arc is best exposed in northwest Nevada as the Triassic-Jurassic Auld Lang Syne basin, which was subsequently closed by the Middle-Late Jurassic Luning-Fencemaker fold-thrust belt. This thrust belt records early crustal thickening and uplift of the Cordillera hinterland. Here, we present preliminary data from coupled field, structural, and analytical investigations of the Auld Lang Syne basin and the Luning-Fencemaker thrust belt. We document important field relationships, cross-cutting intrusions, peak thermal conditions, and Raman Spectroscopy of carboniferous material thermochronology to interpret this important system. Our observations are compared to a global synthesis of back-arc basins to explore how well our knowledge of the Auld Lang Syne basin system is consistent with back arcs globally.