Collaborative Research: Constraining P-T-t-D Paths of Metamorphic Tectonites with the TitaniQ Thermobarometer

智力优势：最近几种微量元素温度计的发展为地质学家提供了强大的新工具，可以约束许多地壳岩石的压力-温度-时间-变形（P-T-t-D）历史，以了解它们的构造和岩石学历史。这种方法的关键是最近开发的一种石英中钛（TitaniQ）温度计，它可以从溶解在石英中的钛的含量中理想地提供T或P信息。这种方法还有待在一个特征明确的环境中进行测试。为此，提出了一项综合的微观结构、岩石学和地球化学研究，以评估来自Strafford Dome杂岩的变质构造岩的P-T-t-D路径。这些岩石记录了在棱砾解理发育过程中的渐进变形，局部记录了S1组构和糜棱岩化的完全转位。S1以富含石英的包裹体的形式保存在石榴石、橄榄石和蓝晶石等矿物中，这表明CL成像结合来自同一样品的不同显微结构背景下的石英中钛的原位分析可以阐明P-T-t-D路径的离散段。电子后向散射和CL成像将用于研究与P-T条件相关的应变场，并提供有关Ti分布的与石英再平衡相关的物理过程的见解。这项研究的独特之处在于，它不仅可以确定温度，还可以确定织物的深度。更广泛的影响：拟议的研究工作将促进构造学、岩石学和地球化学领域的合作。该项目将支持两位早期职业地球科学家（Webb和Thomas）的研究项目，并通过使用尖端技术、实地实践和实验室经验，加强研究生和本科生的教育和培训。学生将获得从微米尺度到盘子尺度的观察联系的经验。这项工作的结果将广泛适用于大陆构造学的许多问题，并在国际会议和同行评议的期刊上发表。本研究过程中收集的样品、现场数据和分析数据将用于L. Webb为UVM高级本科生和研究生开设的“微观结构分析和P-T-t-D路径”课程。显微照片、CL图像和分析数据集将通过美国国家科学基金会支持的变质地球化学数据库系统（MetPetDB）提供给科学界用于研究和教学。

Collaborative Research: Constraining P-T-t-D paths of metamorphic tectoniteswith the TitaniQ thermobarometer Intellectual merit: The recent development of several trace-element thermometers has provided powerful new tools for geologists to constrain pressure-temperature-time-deformation (P-T-t-D) histories of many crustal rocks to understand their tectonic and petrologic histories. Key to this approach is the recent development of a Ti-in-quartz (TitaniQ) thermobarometer that can ideally provide T or P information from the content of Ti dissolved in quartz. This approach remains to be tested in a well-characterized environment. To this end, an integrated microstructural, petrologic, and geochemical study is proposed to evaluate P-T-t-D paths of metamorphic tectonites from well characterized and previously dated gneisses, schists, and mylonites from the Strafford Dome complex (Vermont). These rocks record progressive deformation during crenulation cleavage development and, locally, complete transposition of the S1 fabric and mylonitization. S1 is preserved as quartz-rich inclusions suites in minerals such as garnet, staurolite, and kyanite, suggesting that CL imaging combined with in situ analyses of Ti-in-quartz in different microstructural contexts from the same sample may elucidate discrete segments of the P-T-t-D path. Electron backscatter and CL imaging will be used to investigate the strain field associated with P-T conditions and provide insight into the physical processes associated with quartz reequilibration with respect to Ti distributions. What is unique about this study is the potential to determine not just the temperature, but also the depth at which a fabric is developed. Broader impacts: The proposed research efforts will foster collaboration at the interface of tectonics, petrology, and geochemistry. The project will support the research programs of two early career geoscientists (Webb and Thomas) and enhance graduate and undergraduate student education and training through the use of cutting-edge technology and hands-on field and laboratory experiences. Students will gain experience in linking observations from micron to plate scales. The results of this work will be broadly applicable to many problems in continental tectonics and disseminated at international meetings and in peer reviewed journals. Samples, field data and analytical data collected during the course of this study will be used in L. Webb's class, Microstructural Analysis and P-T-t-D Paths, for senior level undergraduate and graduate students at UVM. Photomicrograghs, CL images, and analytical data sets will be available to the scientific community for research and teaching through an NSF supported Database System for Metamorphic Geochemistry 'MetPetDB'.