Ore Systems, Tectonics and the Geochemical Cycles of Metals

全球地球化学循环使地球或多或少处于稳定状态。 流体-岩石相互作用是帮助维持这些地球化学循环的主要过程，并负责质量（例如，元素）在近地表环境中的迁移（例如，铀矿床）以及更深的地壳（例如，造山型Au矿床）。 虽然我们对某些地球化学循环如碳和硫循环有了相当多的了解，但我们对金属地球化学循环及其与构造和成矿系统的关系的理解还存在差距。确定全球金属地球化学平衡中的这些差距或不一致性可能表明我们对潜在资源的认识存在类似的差距。我的研究旨在通过了解提取，运输和浓缩金属的过程以及大规模（地壳）流体事件与区域，局部和原子水平的质量运输之间的关系来解决这些差距。在这样做的过程中，我计划为科学做出根本性的贡献，这些贡献将在环境科学和矿物勘探中得到应用。大多数具有经济价值的要素（例如，Au、U）以百万分之几（ppm）或更低的浓度存在于地壳中。为了使这些金属能够经济地提取，它们必须以足够的浓度积累在地壳中。因此，必须在适当的时候进行几个过程。同位素可以提供关于这些在自然系统中分布和富集金属的过程的信息。使用传统的轻稳定同位素（H、C、O、N和S）和Pb的分馏作为流体-固体相互作用、地质温度计、质量传输和污染物的示踪剂的实用性已经很好地建立，并且放射性同位素（例如，U-Pb）是流体事件的有用计时器。然而，使用非传统的轻同位素如B和Li，以及过渡-（例如，Fe）和其他重金属同位素（例如，（1）处于婴儿期。因此，在此资助期间，我和我的学生计划将联合收割机传统和非传统同位素系统结合起来，以解决与铀矿石系统有关的一些关键问题。 我们计划将联合收割机的实地观察和对自然样品的分析结合起来，以验证我们的观察和解释。这项工作的新奇在于，将不同的矿物学和同位素技术结合起来，为矿床的成因提供了见解。 这项建议涉及以研究生和本科生的形式对高素质人员进行广泛培训，并与来自其他大学和政府机构的访问科学家进行合作。特别是，提出的协作工作将为学生提供异常广泛和多样化的科学背景，为他们发展未来的研究做好准备。

Global geochemical cycles maintain the Earth in a more-or-less steady state. Fluid-rock interaction is a major process which helps maintain these geochemical cycles and is responsible for mass (e.g., elemental) transport in near-surface environments (e.g., U deposits) as well as the deeper crust (e.g., Orogenic Au deposits). Although we know a considerable amount about certain geochemical cycles such as the carbon and sulfur cycles, there are gaps in our understanding of geochemical cycles of metals and their relation to tectonics and ore systems. Identifying these gaps or inconsistencies in the global metal geochemical balance may point to similar gaps in our knowledge of potential resources. My research aims to address these gaps by understanding the processes that extract, transport and concentrate metals, and the relationship between large-scale (crustal) fluid events and mass transport at the regional, local and atomic levels. In so doing, I plan to make fundamental contributions to science that will find application in the environmental sciences and mineral exploration. Most elements of economic value (e.g., Au, U) occur in the Earth's crust in concentrations of a few parts per million (ppm) or lower. For these metals to be economically extractible they must accumulate in the Earth's crust in sufficient concentrations. Therefore, several processes must occur at the appropriate time. Isotopes can provide information on these processes that distribute and concentrate metals in natural systems. The utility of using the fractionation of traditional light stable isotopes (H, C, O, N, and S) and Pb as tracers of fluid-solid interactions, geothermometers, mass transport and contaminants is well established, and radiogenic isotopes (e.g., U-Pb) are useful chronometers of fluid events. However, the use of non-traditional light isotopes such as B and Li, and transition- (e.g., Fe) and other heavy-metal isotopes (e.g., U), is in its infancy. Therefore, during this funding period my students and I plan to combine traditional and non-traditional isotope systems to address some key questions related to uranium ore systems. We plan to combine field observations and analysis of natural samples to verify our observations and interpretations. The novelty of the work is that diverse mineralogical and isotopic techniques are combined to provide insights into the genesis of mineral deposits. This proposal involves extensive training of Highly Qualified Personnel in the form of graduate and undergraduate students, and collaborative work with visiting scientists from other Universities and government institutions. In particular, the collaborative work proposed will give students an unusually wide and diverse background in science, preparing them to develop the research of the future.