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的发展迅速，文献现在包含来自世界两家研究小组的75篇论文中的数千种同位素分析。这项工作的大部分都集中在天然系统上，并且只有少数实验确定的动力学和平衡分级因子以及相关的交换动力学数据可用于地质相关系统。地球上的Fe同位素组合物的最大变化记录在硫化物中，其中在沉积黄铁矿中发现了几乎55FE/54FE比率的5个腐烂范围，而高温水热硫化物中的3个腐烂范围则在3个腐烂范围内，但在高温和矿物质的Fe同位素分裂机制中，水位和矿物质Fe-S Systems中的贫乏。计划了一项全面的实验计划，以确定在温度范围内水性Fe-S物种和硫化物矿物质之间的Fe同位素分馏，最高为〜250C。实验程序将在涵盖一些最常见的水性和矿物质物种的三个系统中探索同位素分馏。将研究动力学和平衡的Fe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质的Fe同位素组成方面起主要作用。除温度外，我们还将探索pH和痕量金属取代对Fe同位素分馏和交换动力学的影响。 硫化物的铁同位素地球化学已用于研究从生命的起源和进化到水热矿石沉积中金属的来源的问题。通过本研究产生的同位素分级机制的可用性，这些数据的解释将得到增强。此外，将采用新的实验方法，通常适用于其他矿物合成实验研究。研究小组融合了三个机构的同位素和实验地球化学的基本专业知识。该项目将支持和教育几位研究生和三家机构的博物馆。这些包括博士来自加纳的学生和乌拉圭的一位女性后科学家。此外，该研究将涉及一位早期职业助理教授。