COLLABORATIVE RESEARCH: Understanding Climate Change During the Final Stages of Late Paleozoic Gondwanan Glaciation - An Integrated Data-Model Study

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ABSTRACTCOLLABORATIVE RESEARCH: UNDERSTANDING CLIMATE CHANGE DURING THE FINAL STAGES OF LATEPALEOZOIC GONDWANAN GLACIATION - AN INTEGRATED DATA-MODEL STUDYIsabel Montanez, University of California, DavisVladimir Davydov & Mark Schmitz, Boise State UniversityChris Poulsen, University of MichiganNeil Tabor, Southern Methodist UniversityRecently developed paleoclimate archives reveal a much more dynamic transition from the latePaleozoic Gondwanan ice age to a greenhouse world than previously considered - one characterized byconsiderable co-variability in climate and pCO2. Recently documented short-lived (1 to 4 m.y.) episodesof glaciation appear to coincide with large magnitude shifts in atmospheric pCO2, marine and continentaltemperatures and relative sea-level suggesting a CO2-climate-glaciation link. This link, however, remainsuntested. We propose an interdisciplinary study focused on significantly improving our understanding ofthe evolution of the late Paleozoic climate system, and the mechanisms that triggered climate changeduring the Earth's last period of transition from icehouse to greenhouse states. The research is designed totest two hypotheses: (1) that atmospheric CO2 variability was the primary driver for repeated growth andretreat of continental ice sheets, and, in turn, (2) that late Paleozoic ice sheets strongly influenced globalclimate, particularly in the tropics. Specific basins in central and eastern Europe and western Argentinahave been targeted given their stratigraphic and paleogeographic coverage, presence of marine, paralicand paleosol-bearing terrestrial deposits, and their existing biostratigraphy and potential for furtherradiometric dating (i.e., multiple intercalated volcanic tuffs) and biostratigraphic analysis. This researchhas three major objectives:* To establish a radiometrically calibrated, chronostratigraphic framework (Gzhelian to early MiddlePermian) through the integration of new and existing bio-, cyclo-, and chemo-stratigraphic (87Sr/86Sr)data with U/Pb dating of volcanic tuffs, and the application of these integrated data to multiplequantitative tools (CONOP, RASC, CASP, GraphCor).* To further develop and calibrate high-resolution, quantitative proxy records of paleo-atmosphericpCO2, paleo-precipitation, and marine and terrestrial paleo-temperatures. This includes criticalevaluation and further development of new quantitative proxies as well as direct comparison of proxyrecords to sedimentologic evidence for glaciations and 'warmings' in southern Gondwanansuccessions.* Development of a theoretical climate framework for the late Paleozoic glacial-interglacial oscillationsusing three-dimensional climate models to quantify the sensitivity of ice sheets on Gondwana topCO2, determine the role of ice sheets in driving global climate change, and make climate predictionsthat can be tested through comparison with the proxy records.Broader Impacts: The proposed research will offer four major contributions to the broader scientificcommunity: (1) a reconstruction of the late Paleozoic climate system at an unprecedented level ofresolution and accuracy, (2) an important test of the pCO2-climate paradigm for climate evolution throughEarth history, (3) documentation of marine-terrestrial climate linkages at unprecedented temporalresolution for the Paleozoic, and (4) the first test of proposed correlations of cyclothemic successions ineastern Euramerican and North American basins, and of linkages to the Gondwanan glaciosedimentaryrecord. In addition, to the planned cross-disciplinary training of undergraduate and graduate students, thePIs will integrate their research efforts into three educational outreach programs designed to enhance theresearch and teaching opportunities of underrepresented undergraduate students and high school scienceteachers. We will make our data and model simulations available to the greater scientific community byimporting them into the CHRONOS System (and its partner website, PaleoStrat), a web-based interactiveresource with which PI Davydov is directly involved.