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

ABSTRACTCOLLABORATIVE研究:了解晚古生代冈瓦南冰期最后阶段的气候变化——一个综合数据模型研究伊莎贝尔·蒙塔涅兹，加利福尼亚大学，戴维斯·弗拉迪米尔·达维多夫和马克·施米茨，博伊西州立大学，克里斯·波尔森，密歇根大学，尼尔·塔博尔最近开发的古气候档案揭示了从晚古生代冈瓦纳冰期到温室世界的转变比以前认为的要动态得多——一个以气候和二氧化碳分压显著共变为特征的世界。最近记录的短暂的（1到4米）冰期似乎与大气二氧化碳分压、海洋和大陆温度以及相对海平面的大幅度变化相吻合，这表明二氧化碳与气候-冰川之间存在联系。然而，这种联系仍有待检验。我们提出了一项跨学科的研究，重点是显著提高我们对晚古生代气候系统演变的理解，以及在地球从冰窖到温室状态过渡的最后时期引发气候变化的机制。该研究旨在验证两个假设：(1)大气二氧化碳变化是大陆冰盖反复生长和消融的主要驱动因素；(2)晚古生代冰盖对全球气候，特别是热带地区的气候产生强烈影响。中欧和东欧以及阿根廷西部的特定盆地由于其地层和古地理覆盖范围，海相、海陆和含古土壤的陆相沉积物的存在，以及它们现有的生物地层学和进一步辐射测年（即多个夹层火山凝灰岩）和生物地层学分析的潜力而成为研究目标。本研究有三个主要目标：*通过整合新的和现有的生物、旋回和化学地层（87Sr/86Sr）数据与火山凝灰岩的U/Pb定年，并将这些综合数据应用于多种定量工具（CONOP， RASC， CASP, GraphCor），建立一个放射性校准的年代地层格架（Gzhelian至中二叠世早期）。*进一步开发和校准古大气co2、古降水、海洋和陆地古温度的高分辨率定量代理记录。这包括批判性评估和进一步发展新的定量代用品，以及将代用品记录与冈瓦纳南部演替的冰川和“变暖”的沉积学证据进行直接比较。*发展古生代晚期冰期-间冰期振荡的理论气候框架，利用三维气候模型量化冈瓦纳冰盖对表层二氧化碳的敏感性，确定冰盖在驱动全球气候变化中的作用，并通过与代理记录的比较进行气候预测。更广泛的影响：拟议的研究将为更广泛的科学界提供四个主要贡献：(1)以前所未有的分辨率和精度重建了晚古生代气候系统；(2)对整个地球历史上气候演化的pco2 -气候范式进行了重要的检验；(3)以前所未有的古生代时间分辨率记录了海洋-陆地气候联系；(4)首次验证了欧美东部和北美盆地的周期性演替相关性，以及与冈瓦纳冰川沉积记录的联系。此外，除了计划对本科生和研究生进行跨学科培训外，这些pi还将把他们的研究成果整合到三个教育推广项目中，旨在提高代表性不足的本科生和高中科学教师的研究和教学机会。我们将把我们的数据和模型模拟提供给更大的科学界，将它们导入CHRONOS系统（及其合作伙伴网站，palestrat），这是一个基于网络的互动资源，PI Davydov直接参与。

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.