EAR-PF: Tracking rocks from depth to the surface: Coupled (U-Th)/(Pb-He) dating of monazite

EAR-PF：从深处到地表追踪岩石：独居石耦合 (U-Th)/(Pb-He) 测年

• 批准号: 0948158
• 负责人: Emily Peterman
• 金额: $ 17万
• 依托单位: Peterman Emily M
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0948158&HistoricalAwards=false
• 关键词: EAR; PF; Tracking; rocks; depth

Dr. Emily M. Peterman has been granted the NSF Earth Sciences Postdoctoral Fellowship to carry out a research and education plan at Stanford University. This research will develop and calibrate a new technique to determine particle paths within the crust from a single key mineral that is present in many rocks. Monazite is a uranium- and thorium-bearing phosphate that can be analyzed by multiple methods to provide isotopic age information that bear upon both the timing of high-temperature crystallization and subsequent lower-temperature cooling during crustal residence. Furthermore, the trace element and isotopic composition of monazite can be linked to growth conditions within the crust. By combining all of this information, the newly developed approach will improve our ability to quantitatively reconstruct the spatial and temporal nature of crust-forming processes.This comprehensive analysis of the use of monazite as a chronometer for elucidating the formation and evolution of continental crust will impact a broad range of geoscience disciplines, including tectonics, geomorphology, metamorphic petrology, landscape evolution and continental dynamics. By improving the accuracy and precision of monazite isotopic age analysis, this research will improve our ability to constrain geodynamic models of crustal evolution. The details of the new methodology - including the calibration of compositionally dependent effects - may have application to other techniques, and should benefit the geoochronologic community at large. Research methods developed in this project will be integrated into a field-based course to be taught by Peterman in Death Valley. Through this course, undergraduate and graduate students will be taught how to collect samples, analyze data, and publish a paper that constrains the timing of deformation along a major fault that exposes some of the deepest-known exposures of southwestern North American crust. The results from this study will also be incorporated into an outreach demonstration that uses coupled monazite chronometry to provide an animated module that illustrates the mechanics, timing and rates of processes responsible for creating dynamic orogens such as the Himalaya.

Emily M. Peterman 博士已获得美国国家科学基金会地球科学博士后奖学金，在斯坦福大学开展研究和教育计划。这项研究将开发和校准一项新技术，以确定许多岩石中存在的单一关键矿物在地壳内的粒子路径。独居石是一种含铀和钍的磷酸盐，可以通过多种方法进行分析，以提供同位素年龄信息，这些信息与地壳停留期间高温结晶的时间和随后的低温冷却有关。此外，独居石的微量元素和同位素组成与地壳内的生长条件有关。通过结合所有这些信息，新开发的方法将提高我们定量重建地壳形成过程的空间和时间性质的能力。这种对使用独居石作为阐明大陆地壳形成和演化的计时器的综合分析将影响广泛的地球科学学科，包括构造学、地貌学、变质岩石学、地貌演化和大陆动力学。通过提高独居石同位素年龄分析的准确性和精密度，这项研究将提高我们约束地壳演化地球动力学模型的能力。新方法的细节——包括成分相关效应的校准——可能适用于其他技术，并且应该使整个地质年代学界受益。该项目开发的研究方法将被纳入彼得曼在死亡谷教授的实地课程中。通过本课程，本科生和研究生将学习如何收集样本、分析数据并发表论文，限制沿主要断层的变形时间，该断层暴露了北美西南部地壳一些最深的已知暴露部分。这项研究的结果还将被纳入一个外展演示中，该演示使用耦合独居石测时法来提供一个动画模块，该模块说明了负责创建喜马拉雅山等动态造山带的过程的力学、时间和速率。