Behavior of Nd isotopes at the Ocean-Sediment Boundary: Addressing the "Nd Paradox"

海洋-沉积物边界 Nd 同位素的行为：解决“Nd 悖论”

• 批准号: 1147407
• 负责人: Brian Haley
• 金额: $ 43.99万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-15 至 2017-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1147407&HistoricalAwards=false
• 关键词: Behavior; Nd; isotopes; Ocean; Sediment

Neodymium isotope ratios (143Nd/144Nd) are increasingly used as tracers of past ocean circulation patterns. However, our understanding of marine Nd dynamics, and thus the reliability of Nd as an oceanic tracer, is currently complicated by an apparent disconnect between the isotopic compositions of Nd (which are distinctive between ocean basins) and the distribution of elemental Nd (which appears to be driven by water column cycling). It is important to resolve this "Nd paradox" in order to refine tracer studies of past ocean behavior. Prior research suggests that the decoupling of isotopic and elemental Nd may occur near the interface between marine sediments and bottom waters. This study, conducted by researchers at Oregon State University, investigates exchange reactions between dissolved and particulate Nd occurring at and around this interface, with a focus on the influence of diagenetic sedimentary processes on Nd isotope ratios. Porewater, sediment, and water column samples will be collected along the Oregon continental margin and analyzed for Nd isotopes and other relevant tracers (including rare earth elements, carbon, and nitrogen). The resulting dataset will not only help to resolve the Nd paradox, but will also be applied to future conceptual and chemical modeling efforts, which in turn will inform the development of paleoceanographic and paleoclimatic models.This project will be incorporated into the COSEE (Center for Ocean Science Education Excellence) Pacific Partnerships ocean literacy effort. A PRIME (Promoting Research Investigations in the Marine Environment) intern, as well as two OSU students (PhD and undergraduate), will be involved in this research. The project includes international collaboration with a geochemist from the University of Bristol, which will strengthen Oregon State University's analytical capabilities. Funding will also help support an early-career researcher at Oregon State University.

同位素比率（143/144nd）越来越多地用作过去海洋循环模式的示踪剂。但是，我们对海洋ND动力学的理解，因此ND作为海洋示踪剂的可靠性，目前由于ND的同位素组成（在海盆之间与众不同）与元素ND的分布（似乎是由水柱循环驱动）的明显脱节。为了完善过去海洋行为的示踪剂研究，解决此“悖论”很重要。先前的研究表明，同位素和元素ND的解耦可能发生在海洋沉积物和底水之间的界面附近。这项由俄勒冈州立大学的研究人员进行的研究调查了在该界面及其周围发生的溶解和颗粒之间的交换反应，重点是成岩成岩沉积过程对ND同位素比率的影响。将沿俄勒冈大陆边缘收集孔隙水，沉积物和水柱样品，并分析ND同位素和其他相关示踪剂（包括稀土元素，碳和氮）。由此产生的数据集将不仅有助于解决ND悖论，而且还将应用于未来的概念和化学建模工作，进而将为古生物学和古气候模型的发展提供信息。该项目将纳入Cosee（海洋科学教育中心卓越）Pacific Pacific Partnerships海洋文学工作。这项研究将参与一项主要的（促进海洋环境中的研究调查）以及两名OSU学生（博士学位和本科生）。该项目包括与布里斯托大学的地球化学家的国际合作，该公司将增强俄勒冈州立大学的分析能力。资金还将有助于支持俄勒冈州立大学的早期研究员。