COLLABORATIVE RESEARCH: Testing hypotheses for Late Devonian biotic and climatic events via high-precision CA-TIMS U-Pb zircon dating and quantitative correlation tools

合作研究：通过高精度 CA-TIMS U-Pb 锆石测年和定量相关工具检验晚泥盆世生物和气候事件的假设

• 批准号: 1124488
• 负责人: Mark Schmitz
• 金额: $ 15万
• 依托单位: Boise State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1124488&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Testing; hypotheses; Late

COLLABORATIVE RESEARCH: Testing hypotheses for Late Devonian biotic and climatic events via high-precision CA-TIMS U-Pb zircon dating and quantitative correlation toolsMark Schmitz, EAR-1124488Boise State UniversityD. Jeffrey Over, EAR-1124275SUNY GeneseoABSTRACT The Late Devonian period hosts a series of global biological extinction events of such magnitude as to be counted among the major mass extinctions of the Phanerozoic. Yet no consensus has yet been reached regarding the causative mechanisms of extinction and associated changes in marine sedimentation, biogeochemical cycling, sea level and climate. Testing of competing hypotheses for Late Devonian extinctions?which include sea-level fluctuations and regression, climatic cooling, ocean anoxia, bolide impact, and/or massive volcanism?is currently hampered by a lack of sufficient temporal resolution in paleobiological, tectonic and proxy climate records.In this study, a multi-disciplinary research team of paleontologists, biostratigraphers and isotope geochemists will combine high-precision U-Pb zircon geochronology on interstratified volcanic ash beds in key stratigraphic successions with quantitative biostratigraphy applied to a global Late Devonian multi-taxa database compiled from the literature and new high-resolution sampling. The U-Pb geochronology will utilize the chemical abrasion and EARTHTIME quadruple spike isotope dilution methods to measure ca 0.1 Ma resolution ages, which will calibrate the construction of the first highly resolved composite standard for the Late Devonian via constrained optimization. With this high resolution age model the research team will interrogate several fundamental questions relating to the abruptness of the late Devonian biotic events, their global synchrony, and process drivers. Specific hypotheses to be addressed include the synchrony and causality between extraterrestrial impacts or massive volcanism and biotic crises, whether the rates of associated eustatic rise and fall and fluctuations in proxy records of carbon cycling and temperature are consistent with Milankovich-band orbital forcing, and if feedbacks between climate, glacioeustasy, ocean anoxia, and the carbon cycle caused the Late Devonian biotic crises.This research will impact STEM human resource development via participation of undergraduate students in a multi-disciplinary international science team; develop international scientific collaborations; support the science mission of the EARTHTIME geochronology initiative, and its associated inreach and outreach programs; provide fundamentally improved chronologies for numerous other Paleozoic climate studies; and improve our understanding of deep time climate state transitions potentially analogous to those leading to our current icehouse. The scientific process and content of the proposed research will be captured by a parallel NSF-funded STEM education initiative developing a series of web-based learning objects to teach the science of geochronology and Earth history.

合作研究：通过高精度 CA-TIMS U-Pb 锆石测年和定量相关工具测试晚泥盆世生物和气候事件的假设Mark Schmitz，EAR-1124488博伊西州立大学博士。 Jeffrey Over，EAR-1124275SUNY Geneseo 摘要 泥盆纪晚期发生了一系列全球生物灭绝事件，其规模之大足以算作显生宙的主要大规模灭绝事件。然而，关于灭绝的致病机制以及海洋沉积、生物地球化学循环、海平面和气候的相关变化，尚未达成共识。目前，由于古生物学、构造和代理气候缺乏足够的时间分辨率，对晚泥盆世灭绝的竞争假设（包括海平面波动和回归、气候变冷、海洋缺氧、火流星撞击和/或大规模火山活动）的测试受到阻碍在这项研究中，由古生物学家、生物地层学家和同位素地球化学家组成的多学科研究小组将结合高精度U-Pb锆石利用定量生物地层学对关键地层序列中的层间火山灰床进行地质年代学，并将定量生物地层学应用于根据文献和新的高分辨率采样编制的全球晚泥盆世多类群数据库。 U-Pb地质年代学将利用化学磨损和地球四峰同位素稀释方法来测量约0.1 Ma分辨率年龄，这将通过约束优化来校准晚泥盆世第一个高分辨率复合标准的构建。借助这种高分辨率年龄模型，研究小组将探讨与泥盆纪晚期生物事件的突然性、其全球同步性和过程驱动因素有关的几个基本问​​题。 要解决的具体假设包括地外影响或大规模火山活动和生物危机之间的同步性和因果关系，相关的海平面上升和下降的速率以及碳循环和温度代理记录的波动是否与米兰科维奇带轨道强迫一致，以及如果气候、冰川平衡、海洋缺氧和碳循环之间的反馈导致了晚泥盆世生物危机。这项研究将通过参与影响STEM人力资源开发多学科国际科学团队中的本科生；发展国际科学合作；支持 EARTHTIME 地质年代学倡议的科学使命及其相关的内展和外展计划；为许多其他古生代气候研究提供从根本上改进的年表；并提高我们对深层气候状态转变的理解，这些转变可能类似于导致我们当前冰库的转变。拟议研究的科学过程和内容将通过 NSF 资助的一项并行 STEM 教育计划来体现，该计划开发一系列基于网络的学习对象来教授地质年代学和地球历史科学。

项目成果

Recalibrating the Devonian time scale: A new method for integrating radioisotopic and astrochronologic ages in a Bayesian framework

重新校准泥盆纪时间尺度：在贝叶斯框架中整合放射性同位素和天文年代学年龄的新方法

• DOI: 10.1130/b36128.1
• 发表时间: 2021
• 期刊: GSA Bulletin
• 作者: Harrigan, Claire O.;Schmitz, Mark D.;Over, D. Jeffrey;Trayler, Robin B.;Davydov, Vladimir I.
• 通讯作者: Davydov, Vladimir I.