Collaborative Research: Transition Metal Isotope Fractionation During Adsorption to Authigenic Oxides

合作研究：吸附自生氧化物过程中的过渡金属同位素分馏

• 批准号: 0526495
• 负责人: Thomas Spiro
• 金额: $ 15万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0526495&HistoricalAwards=false
• 关键词: Collaborative; Research; Transition; Metal; Isotope

ABSTRACTOCE-0526618OCE-0526495Isotope fractionation during adsorption to authigenic oxide minerals is emerging as an important process for paleoproxy applications of many metals. Adsorptive isotope effects have been demonstrated for Mo and Fe, are strongly suspected for Tl, and are at least likely for Cr and Cd. Such fractionation may affect the ocean isotope budgets of these elements and also have important implications for reconstruction of metal isotope paleorecords from isotopic measurements in authigenic oxides such as marine ferromanganese crusts. To realize this potential, it is essential to quantitatively understand the controls on isotopic fractionation and focus on the experiments and theoretical calculations of the natural samples, which have not been the focus of the community's most current work. In this study, researchers at Arizona State University and Princeton University will carry out a laboratory investigation and quantum chemical modeling to attain the following objectives: (1) quantify the magnitude of isotope fractionation of Cr, Fe, Mo, Cd and Tl during adsorption onto various manganese and iron oxides; (2) assess the sensitivity of these effects to intensive variables such as temperature, pH and salinity; and (3) elucidate the reaction mechanisms causing observed fractionations, including definitive determination of whether they arise from equilibrium isotope exchange or kinetics effects. This information is needed to assess whether these new isotopic tools can be used to understand marine geochemical cycles, reconstruct the chemical evolution of the marine environment or determine the ocean redox history. In terms of broader impacts, the project will support not only the early career development of the Co-PI, but also the training of a graduate student, an undergraduate student, and a post-doc in state-of-the-art analytical geochemistry and theoretical chemistry. It will also enhance the infrastructure for research and education by supporting a partnership between geologists, geochemists, and chemists at four different academic institutions, including two outside the United States, who will integrate experiments, state-of-the-art analytical geochemistry and modern theoretical chemistry.

Abstractoce-0526618OCE-0526495在吸附到身份氧化物矿物质的过程中，异位分馏已成为许多金属古透明应用的重要过程。对于MO和FE，已经证明了Adsorptive同位素效应，对于TL非常怀疑，至少对于CR和CD而言。 这种分馏可能会影响这些元素的海洋同位素预算，并且对金属同位素测量的金属同位素paleorecords的重建也具有重要意义，例如，在诸如海洋法拉曼加纳壳的身份氧化物中的同位素测量值。 要实现这一潜力，必须定量了解同位素分馏的控制，并专注于实验和天然样本的理论计算，这并不是社区最新工作的重点。在这项研究中，亚利桑那州立大学和普林斯顿大学的研究人员将进行实验室研究和量子化学建模，以实现以下目标：（1）量化CR，FE，FE，MO，MO，CD和TL在吸附期间对各种锰和铁氧化物的吸附期间的同位素分馏的大小； （2）评估这些影响对密集变量（例如温度，pH和盐度）的敏感性； （3）阐明导致观察到分馏的反应机制，包括确定它们是由平衡同位素交换还是动力学效应产生的。 需要此信息来评估这些新的同位素工具是否可以用于了解海洋地球化学周期，重建海洋环境的化学演化或确定海洋氧化还原历史。 在更广泛的影响方面，该项目不仅将支持Co-Pi的早期职业发展，还将支持研究生，本科生和最先进的分析地球化学和理论化学的培训。 它还将通过支持四个不同学术机构的地质学家，地球化学家和化学家之间的伙伴关系，包括美国以外的两个，他们将整合实验，先进的分析地球化学和现代理论化学，包括两个不同的学术机构。