Collaborative Research: Th-230 as a Sediment Focusing Indicator: constraints from He-3 in Interplanetary Dust Particles

合作研究：Th-230 作为沉积物聚焦指标：行星际尘埃粒子中 He-3 的限制

• 批准号: 0840430
• 负责人: Jerry McManus
• 金额: $ 9.12万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0840430&HistoricalAwards=false
• 关键词: Collaborative; Research; Th; 230; Sediment

Recently, the 230Th constant-flux proxy (CFP) profiling method of calculating sediment accumulation rates (ARs) has become a topic of significant controversy, especially with respect to the issue of sediment focusing and its quantification. Depending on whether one derives ARs using age models or CFPs leads to vastly different interpretations in paleoceanographic studies. Under this award the PIs will investigate sediment redistribution processes to determine the veracity of the 230Th CFP. They will measure another CFP with an independent source term, namely interplanetary dust particles (IDPs), and the extraterrestrial 3He contained therein. Agreement between 230Th and 3He variations in varied and well-studied depositional environments in the North Atlantic would constitute further support for the use of both CFPs for flux normalization. The data generated on sites with known amounts of sediment focusing and winnowing will help constrain the influence of abyssal currents on IDPs and the sediments carrying adsorbed 230Th, and will provide insights into the extent of hydrodynamic sorting of these particles. When combined with 14C and paired 3He and 230Th measurement on various separated fractions of the fine-grained component of the sediment, the PIs will test the hypotheses that 1) 3He is less sensitive than 230Th to sediment focusing, and 2) the degree to which sediment redistribution processes fractionate 3He-containing IDPs from the 230Th containing portion of the sediment. In the future, the proponents hope to develop a new proxy (3He/230Th ratio) for changes in the strength of deep-sea currents in association with past climatic changes. This project will involve students in their teaching, training and learning.

最近，计算沉积物累积率（ARS）的第230个常数频率代理（CFP）分析方法已成为引起重大争议的话题，尤其是在沉积物聚焦及其量化问题方面。 根据人们是否使用年龄模型或CFPS得出AR会导致古文学研究中的解释截然不同。 根据该奖项，PI将调查沉积物再分配过程，以确定第230 CFP的真实性。 他们将测量另一种具有独立源项的CFP，即星际尘埃颗粒（IDP），其中包含的外星3HE。 在北大西洋的各种和研究充分的沉积环境中，第230至3HE之间的一致性将构成进一步支持两种CFP进行通量归一化的支持。在已知量的沉积物聚焦和奖励的位点生成的数据将有助于限制深渊电流对IDP和带有吸附第230的沉积物的影响，并将提供有关这些颗粒流体动力学分类程度的见解。 When combined with 14C and paired 3He and 230Th measurement on various separated fractions of the fine-grained component of the sediment, the PIs will test the hypotheses that 1) 3He is less sensitive than 230Th to sediment focusing, and 2) the degree to which sediment redistribution processes fractionate 3He-containing IDPs from the 230Th containing portion of the sediment.将来，支持者希望为与过去的气候变化相关的深海电流强度变化而开发新的代理（第3HE/230比率）。 该项目将使学生参与他们的教学，培训和学习。