Platinum Group Element Geochemistry of High-MgO Lavas

高MgO熔岩的铂族元素地球化学

• 批准号: 0509176
• 负责人: Munir Humayun
• 金额: $ 8.21万
• 依托单位: Florida State 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: 2004-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0509176&HistoricalAwards=false
• 关键词: Platinum; Group; Element; Geochemistry; MgO

To better understand the mantle geochemistry of the platinum group elements (PGEs), and the information returned by 186,187Os isotopic studies, we propose to determine the PGE abundances of a global suite of high-MgO lavas of Archean to Phanerozoic age, including komatiites and picrites. The results reported from our lab are based on a precise isotope dilution ICP-MS technique which has been successfully applied for the determination of PGEs in such rocks. We also propose to analyze separated mineral phases and extract, by physical and/or chemical techniques, the carrier phase(s) of the PGEs from these rocks. Proposed localities include high-MgO lavas from the following: Kamennoozero, Vetreny, Onega and Lapland (Baltic Shield); Belingwe (S. Africa); Emeishan (China); Song Da (NW Vietnam); Gorgona (Caribbean); and Iceland. All samples are available in collections held by us or will be generously provided by collaborators from other geochemical studies, particularly previous Os isotopic studies. Our intellectual goals for the proposed study are 1) to establish the rules of PGE behaviour during the high degrees of partial melting, and subsequent fractional crystallization, experienced by komatiites and picrites; 2) to obtain mantle source PGE compositions with which to test the hypotheses of crustal recycling and core-mantle interaction, and to establish, where possible, the mechanism of core-mantle interaction. The proposal supports the salaries of a graduate student and a research scientist, and the research forms the basis of a PhD thesis for the graduate student.

为了更好地了解铂族元素的地幔地球化学，以及186,187Os同位素研究返回的信息，我们建议测定全球太古代至显生宙高镁熔岩的铂族元素丰度，包括科马提岩和苦苦岩。本实验室报道的结果是基于精确的同位素稀释电感耦合等离子体质谱技术，该技术已成功地应用于此类岩石中PGE的测定。我们还建议对分离的矿物相进行分析，并通过物理和/或化学技术从这些岩石中提取PGE的载体相(S)。拟议的地点包括来自以下地区的高镁熔岩：Kamennoozero、Vetreny、Onea和Lapland(波罗的海盾)；Belingwe(南非)；峨眉山(中国)；Song Da(越南西北部)；Gorgona(加勒比海)；以及冰岛。所有样品都可以从我们的收藏中获得，或者将由其他地球化学研究的合作者慷慨提供，特别是以前的Os同位素研究。我们拟议研究的智力目标是：1)建立科马提岩和苦皮岩经历的高度部分熔融和随后的分离结晶过程中PGE的行为规则；2)获得地幔来源的PGE成分，用来检验地壳循环和核幔相互作用的假说，并在可能的情况下建立核-地幔相互作用的机制。该提案支持一名研究生和一名研究科学家的工资，这项研究构成了研究生博士论文的基础。