COLLABORATIVE RESEARCH: RUI: 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：RUI：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: 1124275
• 负责人: D. Jeffrey Over
• 金额: $ 8万
• 依托单位: SUNY College at Geneseo
• 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 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1124275&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; RUI; Testing; hypotheses

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锆石U-Pb定年和定量相关工具检验晚泥盆世生物和气候事件的假设。摘要泥盆纪晚期发生了一系列全球性的生物灭绝事件，其规模之大可以被认为是中生代的主要生物大灭绝事件之一。然而，关于灭绝的成因机制以及海洋沉积、海洋地球化学循环、海平面和气候的相关变化，尚未达成共识。晚泥盆世构造相互竞争假说的检验？包括海平面波动和后退、气候变冷、海洋缺氧、火流星撞击和/或大规模火山活动？目前由于缺乏足够的古生物学、构造和代用气候记录的时间分辨率而受到阻碍。在这项研究中，一个多学科的古生物学家研究小组，生物地层学家和同位素地球化学家将联合收割机结合关键地层序列中层间火山灰层的高精度U-Pb锆石年代学和定量生物地层学，应用于全球晚泥盆世多期分类群数据库从文献和新的高分辨率采样汇编。 U-Pb年代学将利用化学磨蚀法和EARTHTIME四重同位素稀释法测量约0.1Ma分辨率的年龄，通过约束优化，标定晚泥盆世第一个高分辨率合成标准的建立。有了这个高分辨率的年龄模型，研究小组将询问几个与晚泥盆世生物事件的不稳定性、全球同步性和过程驱动因素有关的基本问题。 需要解决的具体假设包括地外撞击或大规模火山活动与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波段轨道强迫一致，以及气候，冰川，海洋缺氧，以及碳循环导致的晚泥盆世生物危机。本研究将通过本科生参与多学科国际科学团队来影响STEM人力资源开发;发展国际科学合作;支持EARTHTIME地质年代学倡议的科学使命，及其相关的深入和拓展计划;为许多其他古生代气候研究提供根本改进的年表;并提高我们对可能类似于导致我们目前冰库的深时气候状态转变的理解。拟议研究的科学过程和内容将由NSF资助的并行STEM教育计划捕获，该计划开发了一系列基于网络的学习对象，以教授地质年代学和地球历史科学。