Carbon Isotope Stratigraphy of the Carboniferous in the Arrow Canyon Range, Southeastern Nevada: Reconstructing Carbon Cycling during a Greenhouse-Icehouse Transition

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0003803Saltzman The proposed research will result in a high-resolution (meter-scale) d13C stratigraphy for nearly 1.3 km of Carboniferous limestones exposed in the Arrow Canyon Range in southeastern Nevada. The Arrow Canyon Range has served a global reference section for the Carboniferous as a result of nearly 40 years of detailed work by academic, industry and government geologists. However, little geochemistry has been done to this point that can be used to address global processes (e.g., carbon cycling, continental weathering). The Mississippian samples for the carbon isotope curve will come from a section at Tungsten Gap and the Pennsylvanian portion will come from the section at Arrow Canyon. The two sections are essentially unfaulted and separated by less than 10 km along strike. Previous work has produced a detailed biostratigraphic framework for both sections using conodont and foraminifers, which will allow for the placement of the carbon isotope curve within a zonal time scale. Previous carbon isotope study in the Lower Mississippian portion of the Arrow Canyon succession has revealed well-preserved trends that can be correlated on a regional to global scale, indicating that the Arrow Canyon Range is well-suited for a detailed geochemical investigation. Carboniferous formations in the Arrow Canyon Range are almost entirely limestone, and make up an upward-shallowing succession during the Mississippian and at least two transgressive-regressive cycles, including cyclothemic deposition, during the Pennsylvanian. The carbon isotope curve will be integrated with similar data sets generated for the Carboniferous elsewhere in North America and Europe in order to test hypotheses about global changes in organic carbon burial rates and riverine weathering fluxes during a Greenhouse to Icehouse transition.