Precise U-Pb Dating of Plinian-Eruption Ashfalls for the Purpose of Time-Scale Calibration and Biostratigraphic Correlation

PI将对单晶进行U-Pb（铀铅）测年 以及少量多颗粒斑晶锆石， 特征的K-Piononites（古火山灰床）， 瑞典、英国和英国的奥陶纪和志留纪层型 美国中部，用于精确的时标 标定和生物地层对比。 拟议 研究将产生内部一致和准确的 中奥陶世-上志留世绝对年代学 英国的层型，并允许直接比较同时代，但 北美、斯堪的纳维亚和美国的不同动物群 王国

PI will perform U-Pb (uranium-lead) dating of single-crystals and small multigrain fractions of phenocrystic zircon from well- characterized K-bentonites (ancient volcanic ash beds) in the Ordovician and Silurian stratotypes of Sweden, Britain and the central United States for the purpose of precise time-scale calibration and biostratigraphic correlation. The proposed research will produce an internally consistent and accurate absolute chronology of the Middle Ordovician through Upper Silurian stratotypes of Britain,and permit direct comparison of coeval but different fauna in North America, Scandinavia and the United Kingdom.