Accomplishment-Based Renewal: Testing Hypothesized CO2 Forcing of Climate, Glaciation, and Biotic Change During the End Carboniferous

基于成就的更新：测试石炭纪末期气候、冰川作用和生物变化的假设二氧化碳强迫

• 批准号: 1024737
• 负责人: Isabel Montañez
• 金额: $ 36.5万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1024737&HistoricalAwards=false
• 关键词: Accomplishment; Based; Renewal; Testing; Hypothesized

ABR: Testing Hypothesized CO2 Forcing of Climate, Glaciation & Biotic Change During the End-CarboniferousIsabel MontanezEAR-1024737ABSTRACTThe focus of this ABR project, through collaboration with colleagues and students, is several key issues regarding the late Paleozoic Ice Age that remain poorly constrained ? i.e., the true magnitude of CO2 shifts, late Paleozoic climate sensitivity, and the nature of the linkages to regional hydroclimate, soil productivity, ice sheet stability, and major restructuring of paleotropical vegetation. The proposed two-component research plan focuses on a ~9 Myr interval of the end-Carboniferous, in particular a hypothesized ?climate event? during the mid-to-late Pennsylvanian transition. Component 1 will evaluate how paleo-pCO2 varied through this interval, and its role in widespread aridity and major vegetation restructuring. Anticipated products include a cyclothem-scale (~105 yr) stomatal index-based record of paleo-pCO2 using two long-ranging and well understood, wetland seed-fern taxa from the Illinois Basin. Integration of xerphytic walchian conifer cuticles from select cyclothems will permit comparison of SI-based CO2 estimates for wet- and dry-land flora and interglacial-glacial-scale CO2 variability. Compound-specific isotopic analysis (äD and ä13C) of the same fossil cuticles will further constrain the rate of onset and magnitude of paleoaridity in the Illinois Basin and test for causality between pCO2, terrestrial paleotropical aridity, and floral ecological restructuring. A proposed 4-year long-duration, plant growth experiment under controlled atmospheric O2:CO2 ratios and inferred Carboniferous climate conditions will provide novel insight into the fossil-based trends. Integration of results with paleobotanical data and our paleoclimate proxy records will be used to develop an appropriate vegetation-feedback component for our climate modeling efforts. The 2nd research component will develop a cyclothem-scale ä18O apatite record using already collected conodonts (CAI 1-3) from two paleotropical basins for the same end-Carboniferous interval. The objective is to test the hypothesis that periods of CO2-forced global warming also drove ice sheet ablation and a reduction in the amplitude of high-frequency (104-105 yr) glacioeustasy. Through collaboration, we will test the potential of the ?carbonate clumped isotope? method to define sea-surface temperatures of precipitation from a suite of exceptionally well-preserved and diagenetically screened brachiopods from the same geological sections. We anticipate that for the best-preserved brachiopods, this approach should permit reconstruction of Pennsylvanian SSTs and ä18Oseawater, and ultimately the most rigorous evaluation of relative changes in ice volume during the LPIA to date.

ABR：测试石炭纪末期气候、冰川和生物变化的假设二氧化碳强迫Isabel MontanezEAR-1024737摘要通过与同事和学生的合作，该 ABR 项目的重点是有关古生代冰河时代晚期的几个关键问题，即仍然受到限制的问题？ 、二氧化碳变化的真实幅度、晚古生代气候敏感性以及与区域联系的性质拟议的两部分研究计划重点关注石炭纪末期的~9 Myr区间，特别是中至中期的吸引性“气候事件”。第 1 部分将评估古 pCO2 在这一时期的变化，以及它在大范围干旱和主要植被重建中的作用。预期的产品包括循环尺度 (~105)。 yr）使用来自伊利诺伊州盆地的两个长期分布且易于理解的湿地种子蕨类群对古 pCO2 进行基于气孔指数的记录，整合来自选定环藻的旱生瓦尔奇亚针叶树角质层将允许比较基于 SI 的湿 CO2 估计值。 - 以及同一化合物的旱地植物区系和间冰期二氧化碳变异性（äD 和 ä13C）。化石角质层将进一步限制伊利诺伊州盆地古干旱的发生速度和强度，并测试 pCO2、陆地古热带干旱和花卉生态重建之间的因果关系。拟在受控大气 O2 下进行为期 4 年的长期植物生长实验：二氧化碳比率和推断的石炭纪气候条件将为基于化石的趋势提供新的见解，将结果与古植物学数据相结合，我们的古气候代理记录将用于。为我们的气候建模工作开发适当的植被反馈组件第二个研究组件将使用从同一石炭纪末期的两个古热带盆地收集的牙形刺（CAI 1-3）开发环线尺度的ä18O磷灰石记录。目的是检验以下假设：二氧化碳导致的全球变暖也导致冰盖消融和高频振幅减小（104-105 年）通过合作，我们将测试“碳酸盐团块同位素”方法的潜力，以从来自相同地质部分的一组保存得非常完好且经过成岩筛选的腕足动物中确定降水的海面温度。 -保存腕足动物，这种方法应该允许重建宾夕法尼亚海表温度和海洋水，并最终对冰量相对变化进行最严格的评估迄今为止的 LPIA。