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With this project we will establish a series of stratigraphic tie points between the uppermost Permian to the Middle Jurassic, i.e. spanning some 100 million years, that allow intercalibration of biochronological, chemostratigraphic, and astrochronological time-series with radio-isotopic ages at the ±200 ka level and are globally valid. Already presented and published results from the precursor projects led to a major breakthrough in the understanding of major life and environmental crises during this period of time. This project proposal now suggests to continue this multidisciplinary approach to integrate and intercalibrate geological processes with climatic and biotic response in the past, using highly precise and accurate U-Pb age determinations on zircon from volcanic ash beds, partly with new objectives and targets: (1) Calibrating the newly established succession of extinctions-recovery cycles affecting the terrestrial and marine biotas during the Late Permian and the Early Triassic, as well as of the accompanying climatic and oceanographic global changes, by high-precision U-Pb geochronology from ash layers and associated volcanics in the Nanpanjiang Basin (Guangxi, south Guizhou, southeastern Yunnan). This basin provides a unique series of ash beds and associated acidic volcanics intercalated within shallow to deep water fossiliferous settings (ammonoids, conodonts, radiolarians). (2) Construct a revised and high resolution calibrated time scale for the Paleozoic-Mesozoic boundary (ammonoids, conodonts, radiolarians, carbon isotopes, palynostratigraphy). Solve the present age contradictions in the Wuchiapingian, Changhsingian, Griesbachian and Dienerian stages generated by inappropriate sampling for radio-isotopic dating and by the misleading use of first appearance data (FAD) of index species for the definition of geological stage boundaries. (3) Quantifying biodiversification rates before, during and after the Triassic-Jurassic boundary (TJB) mass extinction event: Completing the radioisotopic calibration of a unique section in Utcubamba valley (northern Peru), and extending the dataset downwards into the marine upper Triassic (Norian-Rhetian) and upwards into the Lower Jurassic (Sinemurian), and comparing them to the GSSP candidate New York Canyon in Nevada (USA). (4) Quantifying biodiversification rates before, during and after the lower Toarcian global anoxic crisis: Finishing work on a undisturbed and well-exposed section in southern Peru (area of Palca, Tacna), ranging from Sinemurian to Bathonian, and comparing them to sections in Nevada (USA) and northern Chile. Relating the early Toarcian global anoxic event to the eruption of the Karoo flood basalt province in Botswana and Lesotho by high-precision U-Pb zircon dating on zircon and baddeleyite. (5) Use these calibrations for quantifying extinction and recovery rates in terms of post-extinction diversity of each extinction-recovery cycle and for searching any commonalities in the timing and fabric of mass extinctions and recoveries (i.e. comparisons of the post-end Permian with the post-end Triassic and post-Pliensbachien recoveries). (6) Achieving a general improvement the radio-isotopic calibration of the Triassic and the Jurassic, in order to allow for cross-correlations between biostratigraphic schemes based on ammonoids, conodonts, bivalves or radiolarians, between carbon-isotope and biostratigraphic records, and for comparison of sections on different continents that are based on different biostratigraphic schemes with endemic faunas. Since our analytical techniques at highest precision and accuracy are now established and consolidated, we want to make a significant contribution to the Mesozoic timescale using our techniques, as well as exploring ways of intercalibration with volcanic provinces by U-Pb. Our contribution will have a major impact for the improved Mesozoic timescale in the next versions of the Geological Time Scale (GTS2016/20), also used as an important tool for petroleum exploration and exploitation.
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