Trace Element Mobility in the Sub-Solidus: Accessory Mineral Stability, Fluids and the Role of the Rock

知识专长：本项目研究了化学环境对苏格兰Ballachulish火成杂岩（BIC）围岩接触变质作用的副矿物组合和微量元素分布的影响。这一地区是一个理想的天然实验室，可以研究变质作用中流体在控制副矿物稳定性和反应性、矿物结构发育和微量元素流动性方面的作用。确定副矿物化学反应的原因，以及微量元素在岩石中的分布和活动性的后果，对于微量元素在地质过程模拟中的应用以及副矿物数据在解释地壳演化中的效用是至关重要的。研究结果将引起地质年代学家和岩石学家的极大兴趣，他们利用副矿物来理解和量化地质过程。更广泛的影响：该项目将涉及研究生和本科生在研究的各个方面，包括教学和培训的应用和使用“国家的最先进的”仪器。学生将通过多样化的实践经验和建立专业网络的早期阶段，从与合作者的互动中受益匪浅。本科生将被要求为德克萨斯理工大学地球科学研究日，德克萨斯理工大学本科生研究会议准备海报演示，并将有机会参加国家科学会议。此外，副矿物是为隔离有毒或有害物质（如放射性核素）而开发的某些合成材料的天然类似物。这项研究将建立在现有的实验工作的基础上，以量化岩性（化学环境）对地质流体的组成和行为及其对矿物稳定性的影响的作用。此外，许多微量元素（如稀土元素）是经济上重要的，其在地质流体的存在下的行为的改进模型的发展将有助于勘探和开发这些战略上重要的资源的模型。

INTELLECTUAL MERIT: This project addresses the role of chemical environment on accessory mineral assemblages and trace element distribution as a consequence of contact metamorphism of country rocks by the Ballachulish Igneous Complex (BIC), Scotland. This area serves as an ideal natural laboratory to investigate hypotheses concerning the role of fluids in controlling accessory mineral stability and reactivity, development of mineral textures, and trace element mobility during metamorphism. Determining the causes of chemical reactivity of accessory minerals, and the consequences for trace element distribution and mobility in rocks, is fundamentally important for the application of trace elements in modeling geologic processes and the utility of accessory mineral data to interpreting crustal evolution. Research results are expected to be of great interest to geochronologists and petrologists who use accessory minerals to understand and quantify geologic processes. BROADER IMPACTS: The project will involve graduate and undergraduate students in all aspects of the research, including instruction and training in the application and use of "state-of-the-art" instrumentation. Students will greatly benefit from interaction with collaborators by diversifying their practical experience and establishing the early stages of a professional network. Undergraduates will be required to prepare poster presentations for Texas Tech Geosciences Research Day, the Texas Tech Undergraduate Research Conference, and will be provided opportunity to attend national scientific meetings. In addition, accessory minerals are natural analogues of some synthetic materials being developed to sequester toxic or harmful materials (e.g. radionuclides). This study will build upon the existing body of experimental work to quantify the role that lithology (chemical environment) has over the composition and behavior of geologic fluids and their impact on mineral stability. Furthermore, many trace elements (e.g. REEs) are economically important and development of improved models for their behavior in the presence of geologic fluids will contribute to models for exploration and development of these strategically important resources.