Nd and Sr Isotope Tracers of Deep and Shallow Ocean Circulation around South Africa

南非周围深浅海洋环流的 Nd 和 Sr 同位素示踪剂

• 批准号: 0526884
• 负责人: Steven Goldstein
• 金额: $ 36.13万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0526884&HistoricalAwards=false
• 关键词: Nd; Sr; Isotope; Tracers; Deep

ABSTRACTOCE-0526884Two researchers from Lamont-Doherty Earth Observatory will refine and test the utility of neodymium (Nd) isotopes as conservative tracers of water masses, as well as refine the application of the authigenic Fe-Mn-hosted Nd as an archive of the water mass signal and further explore the utility of isotopic signatures of terrigenous detritus as current tracers. Cores, water column samples, and water-borne particulates recovered off the southeast coast of South Africa from a large depth range will be used. Using isotopic and chemical analyses, the following tasks will be carried out: (1) trace Nd isotope ratios of major water masses in an important interocean exchange zone; (2) determine the effects of particle exchange on seawater Nd isotopes along a continental margin; (3) compare Nd isotopes of coretop Fe-Mn leachates to the water masses that bathe the cores: (4) determine if leachates that "fail" the "seawater integrity tests" contain a chemical signature that signals failure; and (5) calibrate the Nd and strontium isotopic signature of Agulhas water column particulates with terrigenous detritus on the seafloor in the context of existing data showing an Agulhas Current signal in South Atlantic sediments. The goal is to calibrate a series of promising circulation tracers that have many future applications in ocean circulation and paleocirculation studies. In terms of broader impacts, availability of calibrated circulation tracers will provide a means of assessing the ocean's role in climate change. It is anticipated that data obtained will be deposited into on-line databases such as SedDB (Integrated Data management for Sediment Geochemistry) and/or CHRONOS (an interactive network of federated data and tools for sedimentary geology and paleobiology), as well as a World Data Center such as NOAA's National Geophysical Data Center. As regards outreach efforts, the PIs plan to continue their participation in the Lamont Open House, wherein they discuss their research with the public. One graduate student will be trained and supported.

拉蒙特-多尔蒂地球天文台的两名研究人员将改进和测试钕（Nd）同位素作为水团保守示踪剂的效用，以及改进自生铁锰主钕作为水团信号档案的应用，并进一步探索陆源碎屑同位素特征作为当前示踪剂的效用。 将使用从南非东南海岸大深度范围内回收的岩心、水柱样本和水性微粒。 利用同位素和化学分析，将进行下列工作：（1）重要的大洋间交换区主要水团的微量Nd同位素比率;（2）确定粒子交换对沿着大陆边海水Nd同位素的影响;（3）比较岩芯顶部铁锰沥滤物与浸泡岩芯的水团的Nd同位素：（4）确定“未通过”“海水完整性测试”的沥滤物是否含有表明未通过测试的化学特征;（5）根据显示南大西洋沉积物中存在阿古拉斯海流信号的现有数据，用海底陆源碎屑校准阿古拉斯水柱微粒的Nd和锶同位素特征。 目标是校准一系列有前途的环流示踪剂，在海洋环流和古环流研究中有许多未来的应用。 就更广泛的影响而言，校准环流示踪剂的可用性将提供一种评估海洋在气候变化中的作用的手段。 预计获得的数据将存入SedDB（沉积物地球化学综合数据管理）和（或）CHRONOS（沉积地质学和古生物学联合数据和工具的交互式网络）等联机数据库，以及NOAA国家地球物理数据中心等世界数据中心。 关于外联工作，研究所计划继续参加拉蒙开放日，在那里他们与公众讨论他们的研究。 一名研究生将得到培训和支助。