Mantle Oxidation States and the Solubility of Oxygen in Diamond

地幔氧化态和氧在钻石中的溶解度

• 批准号: 8903645
• 负责人: Edmond Mathez
• 金额: $ 5.76万
• 依托单位: American Museum Natural History
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-06-01 至 1992-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8903645&HistoricalAwards=false
• 关键词: Mantle; Oxidation; States; Solubility; Oxygen

The nature of mantle fluids and relative stabilities of carbonaceous phases (diamond, graphite, carbonate, fluid) are partly determined by oxidation state. Diamonds are of particular interest in understanding how oxygen fugacity varies in the upper mantle because while most appear to have been transported from relatively oxidized parts of the Earth, some contain extremely reduced mineral inclusions (e.g., iron metal, moissanite). These inclusions and the diamonds that contain them must record a different oxidation state than and be petrogenetically unrelated to the kimberlites that brought them to the surface. Published data and a pilot experiment indicate that measurable quantities of oxygen dissolve in diamond. Therefore, diamonds equilibrated under a range of oxygen fugacities may contain measurably different amounts of oxygen. The pints of this investigation are to: (a) determine the solubility of oxygen in diamond; (b) determine if there are systematic variations in diamond oxygen contents that can be used as qualitative indicators of oxygen fugacity; and (c) search for relationships between diamond oxygen contents and other characteristics, such as inclusion assemblages, nitrogen contents, isotopic compositions and localities. Among the questions to be addressed are, do diamonds with reduced inclusions contain less oxygen than those without such inclusions; what is the significance of the occurrences of moissanite, a mineral which should be stable only under much more reduced conditions than thought to exist in the mantle; might variations in oxygen fugacity in part control the variability in nitrogen contents and carbon isotopic compositions of diamonds. Oxygen will be analyzed at Los Alamos National Laboratory.

地幔流体的性质和地幔流体的相对稳定性 碳质相（金刚石、石墨、碳酸盐、流体）是 部分由氧化态决定。 钻石特别 对了解氧气逸度如何在上层大气中变化的兴趣 地幔，因为虽然大多数似乎是从 地球上相对氧化的部分，有些含有极高的 减少的矿物夹杂物（例如，铁金属、碳硅石）。 这些 内含物和含有它们的钻石必须记录 不同的氧化态，与岩石成因无关 金伯利岩带他们来到地表 公布的数据和试点实验表明， 大量的氧溶解在金刚石中。 因此，钻石 在一定范围的氧逸度下平衡， 可测量的不同数量的氧气。 一品脱这个 研究的目的是：（a）确定氧气在 菱形;（B）确定是否存在系统变化， 金刚石的氧含量，可作为定性 氧逸度指标;以及（c）寻找关系 金刚石氧含量和其他特性之间的关系， 包裹体组合、含氮量、同位素组成 组成和地点。 在需要解决的问题中， 是，减少夹杂物的钻石含有的氧比 那些没有这样的夹杂物;什么是意义的 碳硅石的出现，这种矿物应该是稳定的， 在比想象中更低的条件下， 地幔;氧逸度的变化可能部分地控制了 氮含量和碳同位素组成的变异性 钻石。 氧气将在洛斯阿拉莫斯国家实验室 实验室