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

合作研究：使用 TitaniQ 温压计约束变质构造岩的 P-T-t-D 路径

• 批准号: 0948529
• 负责人: Laura Webb
• 金额: $ 19.45万
• 依托单位: University of Vermont & State Agricultural College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2014-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0948529&HistoricalAwards=false
• 关键词: Collaborative; Research; Constraining; Paths; Metamorphic

Collaborative Research: Constraining P-T-t-D paths of metamorphic tectoniteswith the TitaniQ thermobarometerIntellectual 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'.

合作研究：用 TitaniQ 温压计约束变质构造岩的 P-T-t-D 路径智力价值：最近开发的几种微量元素温度计为地质学家提供了强大的新工具来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石英钛 (TitaniQ) 温压计，它可以理想地根据溶解在石英中的钛含量提供 T 或 P 信息。 这种方法仍有待在充分表征的环境中进行测试。 为此，提出了一项综合的微观结构、岩石学和地球化学研究，以评估来自斯特拉福德圆顶复合体（佛蒙特州）的充分表征和先前测年的片麻岩、片岩和糜棱岩的变质构造岩的 P-T-t-D 路径。这些岩石记录了圆齿解理发育过程中的渐进变形，以及局部 S1 组构和糜棱岩化的完全转位。 S1 以富含石英的包裹体形式保存在石榴石、十字石和蓝晶石等矿物中，这表明 CL 成像与同一样品不同微观结构背景下石英中钛的原位分析相结合，可以阐明 P-T-t-D 的离散部分小路。电子背散射和 CL 成像将用于研究与 P-T 条件相关的应变场，并深入了解与石英再平衡相关的 Ti 分布的物理过程。这项研究的独特之处在于不仅有可能确定温度，还可以确定织物形成的深度。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（韦伯和托马斯）的研究项目，并通过利用尖端技术以及现场和实验室实践经验来加强研究生和本科生的教育和培训。学生将获得将微米级观察结果与平板刻度联系起来的经验。这项工作的结果将广泛适用于大陆构造的许多问题，并在国际会议和同行评审期刊上传播。本研究过程中收集的样本、现场数据和分析数据将用于 L. Webb 为 UVM 高年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 NSF 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。