Molybdenum Isotope Geochemistry in Marine Sediments II: Experimental Determinations of Mo Isotope Fractionation Under Sulfidic Conditions

海洋沉积物中钼同位素地球化学 II：硫化物条件下钼同位素分馏的实验测定

• 批准号: 0727102
• 负责人: James McManus
• 金额: --
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0727102&HistoricalAwards=false
• 关键词: Molybdenum; Isotope; Geochemistry; Marine; Sediments

Transition elements play an essential role in the marine carbon and oxygen cycles, particularly because their stable isotopes offer significant potential for tracing or quantifying past and present chemical processes in the ocean. Molybdenum (Mo), whose marine geochemistry is dominated by the formation of various isotopic signatures, indicates significant potential as a paleoredox indicator.Laboratory experiments quantifying Mo fractionation in oxic environments have been carried out; however, Mo fractionation under reducing conditions have not been empirically investigated. A scientist from Oregon State University proposes a series of experiments to determine the geochemical mechanisms responsible for fractionating Mo isotopes in sulfidic marine environments. It is hypothesized that Mo isotope compositions in reducing continental margin marine sediments are controlled by Mo-sulfide adsorption to pyrite. To test the hypothesis, a suite of experiments would be done to measure sulfide-controlled Mo isotope fractionation. Achieving a quantitative understanding of Mo isotope behavior is needed for interpretating Mo isotope variations in the marine sediment record.In terms of the broader impacts, the principal investigator plans to collaborate with a scientist at Newcastle University. One high school student and one graduate student would be supported and trained as part of this project.

过渡元素在海洋碳和氧循环中发挥着至关重要的作用，特别是因为它们的稳定同位素为追踪或量化海洋中过去和现在的化学过程提供了巨大的潜力。钼（Mo），其海洋地球化学是由各种同位素组成的签名占主导地位，显示出显着的潜力，作为一个paleoredox indicator.Laboratory实验定量Mo分馏在氧化环境中进行了，但是，Mo分馏在还原条件下还没有经验研究。 来自俄勒冈州州立大学的一位科学家提出了一系列实验，以确定硫化物海洋环境中钼同位素分馏的地球化学机制。 推测还原性大陆边缘海相沉积物中钼同位素组成受黄铁矿对钼硫化物的吸附控制。 为了验证这一假设，将进行一系列实验来测量硫化物控制的Mo同位素分馏。 为了解释海洋沉积物记录中的钼同位素变化，需要定量了解钼同位素行为。就更广泛的影响而言，首席研究员计划与纽卡斯尔大学的一位科学家合作。 作为该项目的一部分，将支助和培训一名高中生和一名研究生。