Fold Dating in the Central Appalachian Valley-and-Ridge.

褶皱岩石是常见的、极具美感的山脉特征，它们的时代制约着造山事件的发生时间、区域变形模式、大陆演化和地球的经济成矿--S地壳。这项年代学研究将改进和测试一种基于伊利石粘土测年的新褶皱测年方法，确定美国东部阿巴拉契亚山脉中部的褶皱时间，并展示该方法-S在世界其他地方的潜力。除了该项目的科学目标外，它还为一名博士科学家的研究提供支持，并为本科生提供研究经验，从而促进一个重要的STEM(科学、技术、工程和数学)学科的教育工作队伍的发展。此外，主要调查员的研究和教育宣传将通过专业出版物以及在专业会议和公开陈述中的陈述广泛分发。这项研究还将出现在在线教科书中，并将用于本科生的课堂和实地体验。伊利石测年还直接应用于工业和社会资源需求，因为化石燃料和矿产行业通常涉及本研究中研究的相同地质背景和条件。主要研究人员最近开发了一种利用新晶伊利石的Ar年代学进行褶皱测年的方法，并在墨西哥褶皱冲断带的案例研究中测试了该方法的应用。该方法依赖于单个样品的颗粒级分中的伊利石及其各自的年龄的量化；对过时的颗粒级分的外推确定了变形的年龄及其误差。阿巴拉契亚山谷和山脊项目有两个主要目标：(1)通过开发更好的粘土量化方法来改进伊利石测年方法，同时减少误差估计；(2)确定著名的阿巴拉契亚山脉中部的褶皱年龄，在那里已经假设了正向褶皱序列；目前，褶皱年龄在地层上被划分为上古生代；(3)直接制约美国东部区域古地磁再磁化、矿化和经济矿床的时间。

Folded rocks are common, highly aesthetic features of mountain belts and their ages constrain the timing of mountain building events, regional patterns of deformation, continental evolution and (economic) mineralization of the Earth?s crust. This geochronological study will improve and test a novel fold dating method based on the dating of illite clays, determine timing of folding in the central Appalachian Mountains of the eastern United States, and demonstrate the method?s potential for other locations around the world. In addition to the scientific goals of the project, it is providing support for the research of a doctoral scientist and is providing research experiences for undergraduate students, thus contributing to educational work force development in an important STEM (science, technology, engineering and mathematics) discipline. In addition, the principal investigators research and educational outreach will be broadly distributed through professional publications and by presentations at professional meetings and public presentations. The research will also be feature in an online textbook, and will be used in class and field experiences for undergraduate students. Illite dating also has direct application for industry and societal resource needs, as fossil fuel and mineral industries typically involve the same geologic setting and conditions that are examined in this study.The Principal investigators have recently developed a method for fold dating using argon geochronology of neocrystallized illite and tested its application in a case study of the Mexican Fold-Thrust Belt. The method relies on the quantification of illite in grain-size fractions of a single sample, and their respective ages; extrapolation of dated grain size fractions determines the ages of deformation and their errors. The Appalachian Valley-and-Ridge project has two primary goals: (1) improve the illite dating method by developing better clay quantification approaches that also reduce error estimates; (2) determine fold ages in the well-known central Appalachians, where forward fold progression has been hypothesized; currently, fold ages are stratigraphically bracketed as Upper Paleozoic; (3) directly constrain the timing of regional paleomagnetic remagnetization, mineralization and economic deposits in the eastern United States.