Molybdenum Isotope Geochemistry in Marine Sediments

海洋沉积物中的钼同位素地球化学

• 批准号: 0219651
• 负责人: James McManus
• 金额: $ 26.29万
• 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: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2006-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0219651&HistoricalAwards=false
• 关键词: Molybdenum; Isotope; Geochemistry; Marine; Sediments

ABSTRACTOCE-0219651A PI from Oregon State University plans to test the hypothesis that during authigenic uptake Mo isotopes are fractionated with the lighter isotopes being preferentially taken up relative to the heavy isotopes leaving behind a residual (dissolved) Mo pool that is isotopically heavy relative to seawater. To prove the hypothesis, the PI will analyze existing near surface (top 20 cm) porewater and sediment samples from the Peru/Chile margin and the California margin for 98Mo and 95Mo to assess the early diagenetic behavior of Mo. In addition, a cruise is planned to the Santa Barbara Basin, CA, to collect and analyze deeper sediment and porewater samples from a region where sediments are exposed to continuously changing redox conditions. Results from these samples will determine under what conditions molybdenum isotopes fractionate and whether this fractionation is preserved in the sedimentary record. This information will help determine whether this isotope can be used as a proxy for identifying reducing conditions in sediments.

ABSTRACTOCE-0219651A 来自俄勒冈州立大学的 PI 计划测试以下假设：在自生吸收过程中，钼同位素发生分馏，相对于重同位素，较轻的同位素优先被吸收，留下相对于海水同位素较重的残余（溶解）钼库。 为了证明这一假设，PI 将分析来自秘鲁/智利边缘和加利福尼亚边缘的 98Mo 和 95Mo 现有近地表（顶部 20 厘米）孔隙水和沉积物样本，以评估 Mo 的早期成岩行为。此外，计划前往加利福尼亚州圣巴巴拉盆地，从沉积物持续暴露的区域收集和分析更深的沉积物和孔隙水样本 改变氧化还原条件。 这些样品的结果将确定钼同位素在什么条件下分馏以及这种分馏是否保留在沉积记录中。 该信息将有助于确定该同位素是否可以用作识别沉积物中还原条件的代理。