COLLABORATIVE RESEARCH: The end Guadalupian (ca 260 Ma) biotic crisis: Research into timing, potential causes, and environmental proxies

合作研究：结束瓜达卢皮亚(约260 Ma)生物危机：对时机、潜在原因和环境问题的研究Roland Mundil和Paul Renne：Berkeley Geochron实验室Johathan Payne：斯坦福大学EAR-0923669和EAR-0923620ABSTRACT高分辨率地质年代学有助于测试大陆规模、短期火山事件和环境危机之间拟议的因果关系。这项合作研究的目的是解开瓜达鲁片末期(约260 Ma)大灭绝的时间及其与中国西部峨眉山火山岩省的时间关系。地质年代学研究将与古环境研究(Delta13C地层学)和生物地层学相辅相成。现有的地质年代学和古环境数据表明存在因果联系，但缺乏，不足以可信地检验这一假设，因为约束峨眉山火山活动和灭绝事件的年龄数据不精确和不准确(具有几个Ma的不确定性)，并且Delta13C研究仅限于少数地点的短剖面。因此，根本问题仍然没有得到回答。除了检验因果关系假说外，PI还打算研究(1)灭绝事件在地区和环境中的历时程度(2)晚二叠世生物恢复的速度(3)海洋化学极值(如果存在)与火山活动脉冲以及恢复速度和模式的相关性。详细地，PI将分析记录中国和澳大利亚瓜达卢皮斯末期事件的海洋和陆地剖面中火山灰层中的矿物(锆石、辉长岩)，采用锆石前处理，消除了铅损失的影响，大大提高了高分辨率TIMS锆石U-Pb数据的质量和可靠性。40Ar/39Ar测年将被用作进一步的限制。除了沉积剖面外，他们还将以峨眉山火山产物为目标，分别对锆石、斜纹石和斜长石进行U-Pb和40Ar/39Ar分析。通过U-Pb和40Ar/39Ar年代学与化学和生物地层学的仔细结合，将大大改善中到晚二叠世的时间尺度，并将导致对生物危机及其后果的潜在原因的更现实的评估。特别是，对环境异常的了解已成为地球科学和其他领域研究的主要重点。PIS将通过与加州大学古生物学博物馆和他们的公共推广计划合作，将他们的发现提供给更广泛的受众。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Collaborative Research: The end Guadalupian (ca 260 Ma) biotic crisis: Research into timing, potential causes, and environmental proxiesRoland Mundil and Paul Renne: Berkeley Geochron LaboratoryJohathan Payne: Stanford UniversityEAR-0923669 and EAR-0923620ABSTRACTHigh-resolution geochronology is instrumental in testing proposed causal links between continental-scale, short-term volcanic events and environmental crises. This collaborative research proposal is aimed at unraveling the timing of the end-Guadalupian (ca 260 Ma) mass extinction and its temporal relation to the Emeishan volcanic province in W China. Geochronological research will be complemented with paleo-enviromental studies (delta13C stratigraphy) and biostratigraphy.Currently existing geochronological and paleo-environmental data suggest a causal link but are scarce and insufficient for testing this hypothesis with confidence, because age data constraining the Emeishan volcanism and the extinction event are imprecise and inaccurate (with several Ma uncertainties), and delta13C studies are restricted to short profiles from only a few sites. Therefore, fundamental questions remain unanswered. In addition to testing the hypothesis of a causal link PIs intend to study (1) to what extent the extinction event is diachronous among localities and environments (2) the rate of the biotic recovery in the Late Permian (3) the correlation of extrema in ocean chemistry (if present) with pulses of volcanism and with rates and modes of recovery.In detail, PIs will analyze minerals (zircon, sanidine) from ash-layers within marine and terrestrial sections recording the end-Guadalupian event in China and Australia, applying a zircon pre-treatment which is proven to dramatically improve the quality and reliability of high-resolution TIMS U-Pb zircon data by eliminating the effects of Pb loss. 40Ar/39Ar dating will be employed as a further constraint. In addition to the sedimentary sections they will target Emeishan volcanic products with both U-Pb and 40Ar/39Ar analyses applied to zircon and baddeleyite, and plagioclase, respectively.Through careful integration of U-Pb and 40Ar/39Ar geochronology with chemo- and biostratigraphy, the time scale of the Middle through Late Permian will be greatly improved and will lead to more realistic evaluation of potential causes for the biotic crisis and its aftermath.The research proposed herein is of fundamental importance to understanding first-order processes in Earth History. In particular the understanding of environmental anomalies has become a prime focus of research in Earth Sciences and other areas. PIs will make their findings accessible to a wider audience by collaborating with the University of California Museum of Paleontology and their public outreach program.