RPG: An Investigation of U-Pb Systematics in Conodonts

文摘：氟磷灰石牙形刺元素U-Pb定年研究为生物地层带与绝对年龄的联系提供了一种强有力的地质工具。这种组合消除了从零星分布的火成岩获得的绝对年龄来内插边界年龄的需要。这种内插是当前绝对地质时间尺度中最大的误差来源之一。对于这项规划拨款建议的试点研究，PI将确定早二叠世的阶段界线，这是一个阶段边界的命名和地层位置普遍达成一致的时间，PI可以获得丰富的牙形刺。如果成功，PI将提交一份重大提案，将该方法扩展到二叠纪晚期，届时各阶段的边界和持续时间都会受到持续的争论。解决晚二叠世的地层争议特别重要，因为这一时期包括最广泛的显生宙大灭绝、最低的海平面、基亚曼反转期的结束，以及一些地球化学参数非常快的表观变化速度。该项目的成功将为PI提供一个重要的新工具，以加强她现有的研究，重点是解释保存在海洋生物中的同位素变化记录的全球气候变化。

Abstract: The proposed investigation of U-Pb dating of fluor-apatite conodont elements may provide a powerful geologic tool for linking biostratigraphic zones with absolute ages. The combination eliminates the need to interpolate boundary ages from absolute ages derived from sporadically distributed igneous rocks. This interpolation is one of the largest sources of error in current absolute geologic time scales. For the pilot study proposed for this planning grant, the PI will date the stage boundaries in the Early Permian, a time when the nomenclature and stratigraphic positions of stage boundaries are generally agreed upon, and for which the PI can obtain abundant conodonts. If successful, the PI will submit a major proposal to extend the approach into the Late Permian, a time when the stage boundaries and duration of stages are subject to constant debate. Resolution of the Late Permian stratigraphic controversies is of particular interest because the time period includes the most extensive Phanerozoic mass extinction, the lowest sea level stands, the end of the Kiaman Reversed Period, and very rapid apparent rates of change in a number of geochemical parameters. Success of this project will give the PI an important new tool to enhance her existing research, which focuses on the interpretation of global climate change recorded by isotopic variations preserved in marine organisms.