Collaborative Research: U.S. GEOTRACES Pacific Section: Analysis of 230Th, 232Th and 231Pa

合作研究：美国 GEOTRACES 太平洋部分：230Th、232Th 和 231Pa 分析

• 批准号: 1233903
• 负责人: Richard Edwards
• 金额: $ 41万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1233903&HistoricalAwards=false
• 关键词: Collaborative; Research; U.S.; GEOTRACES; Pacific

The International GEOTRACES program is a multi-national effort to survey (by a series of cross-ocean sections) and understand the global-ocean distribution of trace elements and isotopes in seawater. The GEOTRACES Science Plan has designated the natural radioisotopes 231Pa and 230Th to be key parameters inasmuch as their measurement on all sections is deemed to be critical to the success of entire international ocean science programIn this project, a research team from the Lamont- Doherty Earth Observatory of Columbia University and the University of Minnesota - Twin Cities will undertake measurement of the dissolved and particulate concentrations of 230Th and 231Pa on the US GEOTRACES Peru-Tahiti section, one of the American contributions to the global GEOTRACES effort. Additionally, they will measure dissolved and particulate 232Th concentrations and analyze a limited number of aerosol samples, aerosol leachates, and surface sediments for these radionuclides. These data will be used to: 1) Quantify the rates of boundary scavenging of 231Pa and 230Th associated with the biologically productive Peru upwelling system, 2) Quantify the rates of bottom scavenging of 231Pa and 230Th thought to be associated with resuspended sediments in nepheloid layers, 3) Quantify the uptake of dissolved Th and Pa by metalliferous particles associated with the hydrothermal plume emanating from the East Pacific Rise as well as by authigenic particles formed within the oxygen minimum zone, 4) Quantify the supply of lithogenic 232Th from margin sediments by the combined study of 232Th and 230Th, and 5) Quantify the supply of lithogenic 232Th from aerosols by the combined study of 232Th and 230Th. Through collaboration with other US GEOTRACES investigators, the team expects that this work will provide unprecedented constraints on the processes that supply trace elements to the ocean as well as the processes that remove them. Broader Impacts. The project will provide for the training and support of a postdoctoral research associate and one graduate student.

国际GEOTRACES项目是一项多国努力，通过一系列跨洋剖面来调查和了解海水中微量元素和同位素的全球海洋分布。GEOTRACES科学计划将天然放射性同位素231Pa和230Th指定为关键参数，因为它们在所有剖面上的测量被认为对整个国际海洋科学计划的成功至关重要。来自哥伦比亚大学拉蒙特-多尔蒂地球观测站和明尼苏达大学双城分校的一个研究小组将在美国GEOTRACES秘鲁-塔希提剖面上测量230和231Pa的溶解和颗粒浓度，这是美国对全球GEOTRACES工作的贡献之一。此外，他们将测量溶解的和微粒的232Th浓度，并分析有限数量的气溶胶样本、气溶胶渗滤液和地表沉积物中这些放射性核素的含量。这些资料将用于：1)量化与具有生物生产力的秘鲁上升流系统相关的231Pa和230Th的边界清除速率，2)量化被认为与nepheloid层中再悬浮沉积物相关的231Pa和230Th的底部清除速率，3)量化与东太平洋隆起的热液羽流相关的含金属颗粒对溶解Th和Pa的吸收，以及在氧最小带内形成的自生颗粒。(4)通过对232Th和230Th的联合研究，确定边缘沉积物中产岩232Th的供给；(5)通过对232Th和230Th的联合研究，确定气溶胶中产岩232Th的供给。通过与其他美国GEOTRACES研究人员的合作，该团队希望这项工作将为向海洋提供微量元素的过程以及去除它们的过程提供前所未有的限制。更广泛的影响。该项目将为一名博士后研究员和一名研究生提供培训和支持。