Ore Metals in Magmatic Systems

“该奖项是根据2009年美国复苏和再投资法案(公法第111-5条)资助的。”学术价值：拟议的研究旨在填补我们关于选定元素在硫化物、Fe-(铜)-S-O熔体以及选定氧化物和硅酸盐之间岩浆分配的关键知识空白。在岩浆-热液矿床中，这些元素可分为两类：Mo-W组和Cu-Ag-Au组。该项目建立在前人工作的基础上，通过研究钼、钨、银和金在熔体、硫化物、氧化物和硅酸盐矿物之间的分配，在特定的低方差条件下，实验测定了长英质熔体-蒸汽-卤水-氧化物-磁黄铁矿系统中许多矿石和相关元素的矿物/熔体分配系数。具体来说，这项工作包括：[1]综合评价硫和氧逸度对矿石金属在岩浆相间分配的影响；[2)对选定的元素进行LA-ICPMS分析(其中许多元素在过去很难研究)；以及[3]扩大待研究的矿物/熔体对的范围，以包括形成岩石的硅酸盐。新的和以前收集的划分数据将被用来定量评估有关岩浆过程的相互竞争的假说，这些假说有助于岩浆-热液矿床中的矿石金属多样性。这些模型需要的重要参数是估计在岩浆到达地壳浅层之前失去结晶的金属的比例。广泛的影响：除了收集关于矿石金属分配的重要数据，以及它们在地壳中重新分布的基本原理之外，这些数据还将作为建立斑岩矿床勘探模型的基础。该研究小组在让高中、本科生、硕士和博士生参与积极研究方面有着良好的记录。所有研究生都参与到本科教学中来。此外，教职员工和学生在每年4月举行的马里兰日活动中参与并突出他们的研究；该校园为这一活动平均吸引了约7万名参观者。此外，私营部门还积极参与各种形式的外联活动(退休社区和教会小组的科学讲座；GSA赞助的教育伙伴方案(PEP)；为国家公园管理局在约塞米蒂国家公园为护林员翻译方案提供培训；作为地球科学课程的一部分访问马里兰州当地小学；以及向当地宝石和宝石学会讲课)。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Intellectual Merit: The proposed research is designed to fill critical gaps in our knowledge concerning the magmatic partitioning of selected elements among sulfides, Fe-(Cu)-S-O melts, and selected oxides and silicates. These elements fall into two important groups found in magmatic-hydrothermal ore deposits: the Mo-W group, and the Cu-Ag-Au group. This project builds on previous work on the experimental determination of the mineral/melt partition coefficients of many ore and related elements in felsic melt - vapor - brine - oxide - pyrrhotite systems by studying the partitioning of Mo, W, Ag and Au among melts, sulfides, oxides, and silicate minerals under well specified, low-variance conditions. In detail, this work involves: [1] Comprehensive evaluation of the effects of sulfur and oxygen fugacity on ore metal partitioning among magmatic phases; [2] LA-ICP-MS analysis of selected elements (many of which were difficult to study in the past); and [3] Expand the range of mineral/melt pairs to be investigated to include rock-forming silicates. New and previously collected partitioning data will be used to quantitatively evaluate competing hypotheses regarding magmatic processes that contribute to ore metal diversity in magmatic-hydrothermal deposits. Important parameters needed for such models are estimates of the proportion of metals lost to crystallization before magmas reach shallow crustal depths.Broader Impacts: Beyond the collection of important data on ore metal partitioning, and the fundamentals of their redistribution in the crust, these data will also serve as a basis for the construction of exploration models for porphyry deposits. The research group has an excellent track record of involving a mix of high school, undergraduate, masters and doctoral students in active research. All graduate students are involved in undergraduate teaching. Additionally, faculty and students participate in, and highlight their research in Maryland Day (held in April each year); the campus attracts an average of some 70,000 visitors for this event. Furthermore, the PIs actively participate in outreach in a variety of formats (science lectures in a retirement community and a church group; Partners in Education Program (PEP) sponsored by GSA; training for the Ranger Interpreter Program in Yosemite National Park for the National Park Service; visits to local Maryland elementary schools as part of the earth science curriculum; and lectures to local gem and lapidary societies).