CAREER: Middle and Late Cenozoic Surface Uplift and Climate along the Strike of the Rocky Mountains: Refining the Development of an Intracontinental Mountain Belt

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The Rocky Mountains of the western North America is the premier example of intracontinental mountain belts. Thick Cretaceous marine deposits provide unambiguous evidence that the region was near sea level at about 80 Ma ago. However, the history of subsequent vertical movements that formed present topography are less well constrained, yet crucial for understanding the tectonic processes and driving forces by which mountains form in continental interiors. This project aims to constrain the surface uplift of the Rocky Mountains and western Great Plains and associated climate changes during the last 35 million years. State-of-the-art isotopic methods will be used to estimate the paleotopography along transects in the northern and southern Rocky Mountains. The results will test the hypothesis that the timing and magnitude of uplift of the Rockies varied along its length, variations that can constrain the complex geodynamic processes the formed the Rockies during the this time period. The educational component of this CAREER award involve concerted efforts to engage students from underrepresented minorities in STEM and to provide teaching training to graduate students to better prepare them for academic careers. Specifically, the project will introduce professional activities and career outlooks of geoscientists to about 100 underrepresented minority high-school students in east Texas through a two-day long GEOCAMP, involve underrepresented high-school and undergraduate students in research, and train doctoral students to implement best practices in teaching for diverse learners as part of successful professional careers.Recent geologic and geophysical observations of this classic intracontinental mountain belt demonstrate that the geodynamic drivers of Rocky Mountain uplift are complex and include: (1) late Cretaceous-early Eocene crustal thickening and shortening, or mantle dynamic processes related to low-angle subduction or the removal of an oceanic plateau; (2) middle Cenozoic detachment of oceanic slab; and/or (3) late Cenozoic mantle upwelling and thermal isostasy. The timing of occurrence and the role each mechanism played probably varied along the strike of the range. This project explores the idea that the timing and magnitude of the uplift of the Rockies varied along strike, and that these variations resulted from complex, but decipherable, geodynamic processes during the mid- to late Cenozoic. Specifically, the project will: (1) calibrate clumped isotope geothermometer of Quaternary fluvial carbonate cement in order to evaluate its application to paleoelevation and paleoclimate reconstructions; (2) improve the chronostratigraphy of the middle and upper Cenozoic strata in the Rockies and adjacent Great Plains as well as east Texas by determination depositional ages using detrital and tuff zircon U-Pb geochronology; and (3) document the paleotopographic and paleoclimatic evolution of the Rockies and the adjacent Great Plains along strike using carbonate clumped isotope and volcanic glass hydrogen isotope paleoaltimeters in order to understand the tectonic processes of the formation of the Rockies and associated climate changes during the middle and late Cenozoic.