Spectroscopic studies of crustal fluids

我的研究计划的目标是了解稀有元素，如钽、Nb和稀土元素，是如何以溶解成分的形式存在于地壳内的流体和熔体中的，并利用这一知识更准确地模拟稀土元素成矿等地球化学过程。该方法由两部分组成：[1]详细分析流体和熔体包裹体(即矿物中捕获的微小流体或熔体样品)，[2]直接研究地质相关温度和压力下相对简单的实验流体和熔体系统。从主要矿藏收集的流体和熔体包裹体的化学成分将使用补充的微量分析技术进行测定。然后，这些数据将被用来准备实验熔体和流体系统，这些系统将在钻石窗口单元中使用来自同步辐射光源的高亮度X射线，在高温高压下直接进行分析。获得的X射线发射和吸收光谱数据将为了解与熔体或固相共存的水溶液的结构和组成提供新的和重要的见解。这些数据是理解地球内热流体对稀有元素迁移和沉积的化学控制所必需的。这项研究的结果将增强我们预测稀有元素可能聚集在哪里形成矿床的能力，并提高我们解释受热液(即热水)作用影响的岩石中化学指纹的能力。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上具有更广泛的应用。

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.