Collaborative Proposal: Fluid flow metamorphism and strain localization in mid-crustal shear zones

本项目研究地壳中部地区（深度大于12公里）断层带的成分和强度与流体、变质作用和变形局部化之间的关系。该项目的重点是与犹他州的筏河变质核杂岩有关的韧性断层带，以限制断层作用期间流体的来源和数量。这项研究结合了野外地质测绘、矿物结构分析、化学分析和分析，以确定沿着断层运动的时间。该项目有可能将分析数据与特定的流体来源联系起来，并更好地限制地壳尺度的流体流动。该项目由一名早期职业教师领导，包括硕士研究生和本科生。路易斯安那大学拉斐特分校的第一代和少数民族大学生也参与其中。该项目包括一个外展工作，以支持K-12教育在农村西部北卡罗来纳州，包括地质时间资源开发的本科生。该项目的目标是提高流体岩石相互作用的理解与变质核杂岩有关的剥离剪切带。含水变质矿物记录了地壳深处存在的大气流体。尽管有明确的记录，流星流体下降到中，以较低的地壳深度，许多化学和岩石学的不一致仍然存在。在造山塌陷过程中，上地壳通过脆性正断层作用减薄，而韧性下地壳侧向流动。拉张局部化最终导致拆离剪切带和变质核杂岩的形成。下地壳中的韧性伸展的特征是高热流、花岗岩侵入和混合片麻岩穹丘，与变质/岩浆流体有关。在折返过程中，有两个流体水库（岩浆/变质和大气降水从地表水源）之间的竞争。该项目利用氢、氧稳定同位素数据作为流体来源和流体-岩石交换的示踪剂，提供大陆伸展过程中流体-岩石相互作用的制约。将同位素数据与特定流体源联系起来，以更好地约束地壳尺度流体流动的水文学，从而弥合实验得出的岩石强度之间的差距，该项目由地球科学部的构造计划和刺激竞争性研究的既定计划（EPSCoR）共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project investigates the relationship between fluids, metamorphism, and localization of deformation on the composition and strength of fault zones in middle regions of the crust (depths greater than 12 kilometers). The project focuses on the ductile fault zone associated with the Raft River metamorphic core complex in Utah, in order to constrain both the source and the amount of fluid during faulting. The study incorporates geologic mapping in the field, analyses of mineral structures, chemical analyses, and analyses to determine the timing of movement along the fault. The project has the potential to tie analytic data to specific fluid sources and better constrain fluid flow at a crustal-scale. This project is led by an early career faculty member and includes Masters-level graduate and undergraduate students. First-generation and minority college students at the University of Louisiana at Lafayette are also involved. The project incorporates an outreach effort to support K-12 education in rural western North Carolina that includes geologic time resources developed by undergraduate students.The goal of this project is to improve the understanding of fluid-rock interaction in detachment shear zones associated with metamorphic core complexes. Hydrous metamorphic minerals record the presence of meteoric fluids at great depths within the crust. Despite the clear record of meteoric fluids down to mid- to lower-crustal depths, many chemical and petrologic inconsistencies remain. During orogenic collapse, the upper crust thins by brittle normal faulting while the ductile lower crust flows laterally. Localization of extension eventually leads to the formation of a detachment shear zone and metamorphic core complex. Ductile extension in the lower crust is characterized by high heat fluxes, granitic intrusion, and migmatitic gneiss domes, associated with metamorphic/magmatic fluids. During exhumation, there is competition between two fluid reservoirs (magmatic/metamorphic and meteoric water from surface sources). This project uses hydrogen and oxygen stable isotope data as tracers of fluid source and fluid-rock exchange to provide constraints on fluid-rock interaction during continental extension. Isotopic data is linked to specific fluid sources to better constrain the hydrology of crustal-scale fluid flow, in order to bridge the gap between experimentally-derived rock strengths, and field observations.This project is jointly funded by the Tectonics program in the Division of Earth Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.