Collaborative Research: Experimental Determination of Iron (Fe) Isotope Fractionations in Sulfide Minerals

合作研究：硫化矿物中铁 (Fe) 同位素分馏的实验测定

• 批准号: 0635523
• 负责人: Gregory Druschel
• 金额: --
• 依托单位: University of Vermont & State Agricultural College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0635523&HistoricalAwards=false
• 关键词: Collaborative; Research; Experimental; Determination; Iron

Intellectual Merit. The field of Iron (Fe) isotope geochemistry has grown rapidly and the literature now contains several thousand isotopic analyses in over 75 papers from two-dozen research groups in the world. Most of this work has focused on natural systems, and only a handful of experimentally determined kinetic and equilibrium fractionation factors and associated exchange kinetic data are available for geologically relevant systems. The largest variations in Fe isotope compositions on Earth are recorded in sulfides, where almost a 5 permil range in 56Fe/54Fe ratios is found in sedimentary pyrite and a 3 permil range in high-temperature hydrothermal sulfides, and yet Fe isotope fractionation mechanisms in aqueous and mineral Fe-S systems poorly known. A comprehensive experimental program is planned for determining the Fe isotope fractionations among aqueous Fe-S species and sulfide minerals over the temperature range up to ~250 C. The experimental program will explore isotopic fractionations in three systems covering some of the most common aqueous and mineral species. Both kinetic and equilibrium Fe isotope fractionations will be investigated, including exploration of different sulfide formation pathways and their associated isotopic exchange kinetics, issues that may play a major role in determining the Fe isotope compositions of sulfide minerals. In addition to temperature, we will explore the effects of pH and trace metal substitution on Fe isotope fractionation and exchange kinetics.Broader Impacts. Iron isotope geochemistry of sulfides has been used to investigate problems ranging from the origin and evolution of life to the sources of metals in hydrothermal ore deposits. Interpretations of these data will be enhanced by availability of isotopic fractionation mechanisms generated by this study. In addition, new experimental approaches will be employed that will be generally applicable to other experimental studies of mineral synthesis. The research team blends essential expertise in isotope and experimental geochemistry from three institutions. The project will support and educate several graduate students and a post-doc from the three institutions. These include a Ph.D. student from Ghana and a female post-doctoral scientist from Uruguay. In addition, the research will involve an early-career Assistant Professor.

智力优点。 铁 (Fe) 同位素地球化学领域发展迅速，目前文献中包含来自世界上两个研究小组的超过 75 篇论文中的数千项同位素分析。这项工作大部分集中在自然系统上，只有少数通过实验确定的动力学和平衡分馏因子以及相关的交换动力学数据可用于地质相关系统。地球上 Fe 同位素组成的最大变化记录在硫化物中，其中在沉积黄铁矿中发现了 56Fe/54Fe 比率的几乎 5 个百分点的范围，在高温热液硫化物中发现了 3 个百分点的范围，但在水相中的 Fe 同位素分馏机制和矿物 Fe-S 系统知之甚少。计划进行一项综合实验计划，用于确定水相 Fe-S 物种和硫化物矿物在高达 ~250 C 的温度范围内的铁同位素分馏。该实验计划将探索三个系统中的同位素分馏，涵盖一些最常见的水相和矿物物种。将研究动力学和平衡铁同位素分馏，包括探索不同硫化物形成途径及其相关的同位素交换动力学，这些问题可能在确定硫化物矿物的铁同位素组成方面发挥重要作用。除了温度之外，我们还将探讨 pH 值和痕量金属替代对 Fe 同位素分馏和交换动力学的影响。更广泛的影响。 硫化物的铁同位素地球化学已被用来研究从生命的起源和进化到热液矿床中的金属来源等问题。本研究产生的同位素分馏机制的可用性将增强对这些数据的解释。此外，还将采用新的实验方法，这些方法通常适用于矿物合成的其他实验研究。该研究团队融合了三个机构在同位素和实验地球化学方面的基本专业知识。该项目将支持和教育来自这三个机构的几名研究生和一名博士后。其中包括博士学位。来自加纳的学生和来自乌拉圭的女博士后科学家。此外，该研究还将涉及一名职业生涯早期的助理教授。