Spectroscopic studies of crustal fluids

我的研究计划的目标是了解稀有元素，如钽、铌和镧系元素，如何作为溶解成分存在于地球地壳内的流体和熔体中，并利用这些知识更准确地模拟地球化学过程，如稀有元素矿的形成。提出的方法包括两部分：[1]对流体和熔体包裹体（即矿物中捕获的流体或熔体的微小样本）的详细分析，[2]在地质相关温度和压力下对相对简单的实验流体和熔体系统进行直接研究。从主要矿床收集的流体和熔体包裹体的化学成分将使用互补的微分析技术来确定。然后，这些数据将用于准备实验熔体和流体系统，这些系统将在金刚石窗口细胞的高压和高温下直接分析，使用来自同步加速器光源的高亮度x射线。获得的x射线发射和吸收光谱数据将为与熔体或固相共存的水相流体的结构和组成提供新的重要见解。需要这些数据来了解地球内部热流体对稀有元素运输和沉积的化学控制。这项研究的结果将提高我们预测稀有元素可能集中在哪里形成矿床的能力，并提高我们解释受热液（即热水）过程影响的岩石中的化学指纹的能力。此外，所采用的新方法和获得的数据在解决工业锅炉腐蚀、有毒废物降解和放射性废物限制等问题方面具有广泛的应用前景。

The goal of my research program is to understand how rare elements, such as tantalum, niobium and lanthanides, exist as dissolved constituents in fluids and melts within the crust of the Earth, and to use this knowledge to more accurately model geochemical processes such as rare element ore formation. The method proposed consists of two parts: [1] detailed analyses of fluid and melt inclusions (i.e., tiny samples of fluid or melt trapped within minerals), and [2] direct studies of relatively simple experimental fluid and melt systems at geologically relevant temperatures and pressures. The chemical composition of fluid and melt inclusions collected from major ore deposits will be determined using complementary micro-analytical techniques. These data will then be used to prepare experimental melt and fluid systems that will be directly analyzed at elevated pressures and temperatures in a diamond window cell, using high brilliance x-rays from a synchrotron light source. The x-ray emission and absorption spectroscopic data obtained will provide new and important insights into the structure and composition of aqueous fluids coexisting with melts or solid phases. These data are needed to understand the chemical controls of rare element transport and deposition by hot fluids within the Earth. The results of this research will enhance our ability to predict where rare elements may concentrate to form ore deposits and improve our ability to interpret chemical fingerprints in rocks that were influenced by hydrothermal (i.e., hot water) processes. Furthermore, the new methods employed and the data obtained have wider application to solving problems such as industrial boiler corrosion, degradation of toxic wastes, and the confinement of radioactive wastes.