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.

来自Lamont-Doherty地球天文台的两名研究人员将改进和测试钕（Nd）同位素作为水质量保守示踪剂的实用性，以及改进自生fe - mn -负载Nd作为水质量信号存档的应用，并进一步探索陆源碎屑同位素特征作为电流示踪剂的实用性。将使用在南非东南海岸从大深度范围内回收的岩心、水柱样本和水性颗粒。利用同位素和化学分析，将开展以下工作：(1)重要洋间交换带主要水体微量Nd同位素比值；(2)确定颗粒交换对大陆边缘海水Nd同位素的影响；(3)将岩心顶部Fe-Mn渗滤液的Nd同位素与浸没岩心的水团进行比较；(4)确定“不合格”的“海水完整性测试”的渗滤液是否含有表明不合格的化学特征；(5)在南大西洋沉积物中显示阿古拉斯流信号的现有数据背景下，用海底陆源碎屑对阿古拉斯水柱颗粒的Nd和锶同位素特征进行校准。目标是校准一系列有前途的环流示踪剂，这些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联机数据库，如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互动网络），以及世界数据中心，如NOAA的国家地球物理数据中心。在外联工作方面，pi计划继续参加拉蒙特开放日，在那里他们与公众讨论他们的研究。将培训和支持一名研究生。