Collaborative Research: Refinement of the Late Permian and Early Triassic Time Scale through Integrated Ar/Ar and U/Pb Radioisotopic Dating and Magnetostratigraphy

合作研究：通过综合 Ar/Ar 和 U/Pb 放射性同位素测年和磁性地层学细化晚二叠世和早三叠世时间尺度

• 批准号: 9614512
• 负责人: Maureen Steiner
• 金额: $ 4.3万
• 依托单位: University of Wyoming
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-01 至 1999-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9614512&HistoricalAwards=false
• 关键词: Collaborative; Research; Refinement; Late; Permian

9614512 Steiner Environmental extrema at the end of the Paleozoic are manifest in evidence for profound marine regression, severe faunal and floral extinctions, and geochemical and isotopic anomalies (e.g. Holser and Magaritz, 1987; Erwin, 1993; Veevers et al., 1994). The search for a cause or causes, as well as establishing genetic links between the observed phenomena, is hindered by a paucity of reliable geochronologic data. Though the Permian-Triassic (P-T) boundary is now reasonably well dated, much work remains to test whether the boundary events were globally isochronous and to establish the time scale of events before and after the boundary. Whether the extinctions were protracted or rapid, or occurred in pulses, relies on better calibration of the time scale. The research proposed herein would provide high-precision Ar/Ar and U/Pb dates for tephras combined with magnetostratigraphic data, which would vastly improve the resolution of the time scale. Establishing a well-calibrated magnetic polarity time scale will facilitate global correlations and help obviate problems arising from faunal provincialism and possible diachronism of biostratigraphic boundaries. The proposed research would concentrate on sections in the western interior U.S. for which many data and samples already been obtained. The project will also include geochronologic work and paleomagnetic feasibility studies are proposed which would help determine whether sections in Argentina, Australia, China, Greenland, New Zealand, and South Africa merit future research towards the goals of this project.

小行星9614512 古生代末期的环境极端现象表现为深刻的海退、严重的动物群和植物群灭绝以及地球化学和同位素异常（例如，Holser和Magaritz，1987年; Erwin，1993年; Veevers等人，1994年）。 缺乏可靠的地质年代学数据，阻碍了寻找一个或多个原因以及在所观察到的现象之间建立遗传联系。 虽然二叠纪-三叠纪（P-T）界线的年代已经相当确定，但仍有许多工作要做，以检验界线事件是否具有全球等时性，并确定界线前后事件的时间尺度。 无论是持久的或快速的，或发生在脉冲，依赖于更好的校准的时间尺度。 本文提出的研究将提供高精度的Ar/Ar和U/Pb年龄的火山岩结合磁性地层学数据，这将大大提高时间尺度的分辨率。 建立一个校准良好的磁极性时间尺度将有助于全球的相关性，并有助于解决动物区系的地方性和可能的生物地层边界的穿时性所产生的问题。 拟议的研究将集中在美国西部内陆的部分，已经获得了许多数据和样本。 该项目还将包括地质年代学工作，并提出了古地磁可行性研究，这将有助于确定阿根廷、澳大利亚、中国、格陵兰、新西兰和南非的部分是否值得为实现该项目的目标进行未来的研究。