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 (PGE) 的地幔地球化学以及 186,187Os 同位素研究返回的信息，我们建议确定太古宙至显生宙时代全球一组高 MgO 熔岩的 PGE 丰度，包括科马提岩和苦味石。我们实验室报告的结果基于精确同位素稀释 ICP-MS 技术，该技术已成功应用于此类岩石中 PGE 的测定。我们还建议分析分离的矿物相，并通过物理和/或化学技术从这些岩石中提取铂族元素的载体相。拟议地点包括来自以下地区的高 MgO 熔岩：Kamennoozero、Vetreny、Onega 和 Lapland（波罗的海地盾）； Belingwe（南非）；峨眉山（中国）；宋达（越南西北部）；戈尔戈纳（加勒比海）；和冰岛。所有样品均由我们收藏，或由其他地球化学研究的合作者慷慨提供，特别是之前的锇同位素研究。我们拟议研究的智力目标是 1) 建立科马提石和苦味石经历的高度部分熔化和随后的分级结晶过程中 PGE 行为的规则； 2）获取地幔源PGE成分，用其检验地壳循环和核幔相互作用的假设，并在可能的情况下建立核幔相互作用的机制。该提案支持研究生和研究科学家的工资，并且该研究构成了研究生博士论文的基础。