Nanoscale Structure and Chemistry of Minerals and Mineral Coatings

矿物和矿物涂层的纳米结构和化学

• 批准号: 0409071
• 负责人: David Veblen
• 金额: $ 29.36万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2006-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0409071&HistoricalAwards=false
• 关键词: Nanoscale; Structure; Chemistry; Minerals; Mineral

The proposed research applies advanced transmission electron microscopy (TEM) to problems in mineralogy, petrology, and geochemistry. The projects encompassed by this Accomplishment-based renewal proposal aim to understand the crystal chemistry of minerals and their reactions at the sub nanometer scale. The grains of many shallow sand and sandstone aquifers possess coatings that are commonly assumed to be Fe/Al oxides and oxyhydroxides, but TEM studies show they are predominantly amorphous and poorly crystallized silicate materials. Coatings from a contaminated aquifer on Cape Cod will be characterized in detail; including samples reacted with aqueous Zn solutions. Results will show which phases are responsible for metal sorption and penetration depth into the coating. Additional studies will assess chemical segregation on extended defects in minerals. Analysis of c domain structures in calcian dolomite and twin boundaries in augite will detect Ca enrichment or depletion. The sequence of reactions during multistage replacement of actinolite by anthophyllite will be tracked to illuminate such metamorphic reactions. Renewed NSF support will continue to make important contributions to education and advanced instrumentation infrastructure at Johns Hopkins. It will also produce new understanding of molecular-scale processes in minerals. Society will benefit from the research through improvements in modeling toxic metals in coated-sand aquifers, potentially affecting the quality of water we drink and use in agriculture.

拟议的研究应用先进的透射电子显微镜（TEM）的矿物学，岩石学和地球化学的问题。这个基于成就的更新提案所包含的项目旨在了解矿物的晶体化学及其在亚纳米尺度上的反应。 许多浅砂和砂岩含水层的颗粒具有通常被认为是铁/铝氧化物和羟基氧化物的涂层，但TEM研究表明，它们主要是无定形和结晶不良的硅酸盐材料。涂层从污染的含水层科德角将详细的特点，包括样品与锌的水溶液反应。结果将显示哪些相负责金属吸附和渗透到涂层中的深度。 进一步的研究将评估矿物中扩展缺陷的化学偏析。钙白云岩中的c畴结构和普通辉石中的孪晶边界的分析将检测Ca的富集或贫化。在阳起石被直闪石多阶段置换过程中的反应顺序将被追踪以阐明这种变质反应。新的NSF支持将继续为约翰霍普金斯大学的教育和先进仪器基础设施做出重要贡献。它还将产生对矿物分子尺度过程的新理解。社会将受益于这项研究，通过改进模型中的有毒金属涂层砂含水层，可能会影响我们饮用水和农业用水的质量。