231Pa/230Th profiles from highly accumulating Atlantic sediment cores - a proxy for deep water circulation over the past 30,000 years

来自高度积累的大西洋沉积物岩心的 231Pa/230Th 剖面 - 过去 30,000 年深水循环的代表

• 批准号: 48922712
• 负责人: Professor Dr. Augusto Mangini
• 金额: --
• 依托单位: Institut für Umweltphysik
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/48922712?language=en
• 关键词: 231Pa; 230Th; profiles; highly; accumulating

In the Atlantic Ocean sedimentary 231Pa/230Th below the production ratio of 0.093 are believed to mirror the advective export of 231Pa to the Southern Ocean due to the meridional overturning circulation (MOC). Times of shifted 231Pa/230Th related with prominent events of cooling and warming support the conclusion that variations in the MOC may incite climate changes. However, the impact of boundary scavenging on the 231Pa/230Th in the glacial Atlantic is a great matter of discussion.The goal of this project is to better understand the behaviour of 231Pa/230Th in Holocene and Glacial sediments both, in the open Ocean and in the upwelling areas in the East Atlantic. The ability to quantify possible boundary scavenging effects will substantially improve our understanding and the interpretation of sedimentary 231Pa/230Th-records as a proxy for the strength of MOC. To approach this goal sedimentary 231Pa/230Th profiles from two high-productivity cores off the coast of Namibia and one off West-Africa are compared with those from the North-, West-, and South- Atlantic Ocean. For the first time 231Pa/230Th from high productivity sediment cores from the African margin at adequate accuracy are being measured by AMS and ICP-MS. The analysis is focused on the last 30 kyr. The high accumulation rates of the selected sediment cores allow a very good time resolution. Therefore, it will be possible to examine the response of the sedimentary 231Pa/230Th to several short-term climate events (e.g. Heinrich Events).

在大西洋沉积层中，231 Pa/230 Th的生产比小于0.093，反映了南大洋231 Pa的平流输出。231 Pa/230 Th的变化与显著的变冷和变暖事件有关，支持MOC的变化可能引起气候变化的结论。然而，边界清除对大西洋冰川沉积物中~（231）Pa/~（230）Th的影响是一个值得讨论的问题，本项目的目标是更好地了解大西洋东部开阔洋和上升流区全新世和冰川沉积物中~（231）Pa/~（230）Th的行为。量化可能的边界清除效应的能力将大大提高我们的理解和解释的沉积231 Pa/230 Th记录作为代理的MOC的强度。为了实现这一目标，将纳米比亚海岸外的两个高生产率岩心和西非海岸外的一个岩心的沉积231 Pa/230 Th剖面与北大西洋、西大西洋和南大西洋的剖面进行了比较。第一次231 Pa/230 Th从高生产力的沉积物芯从非洲边缘在足够的精度正在测量AMS和ICP-MS。分析的重点是在过去的30 kyr。所选沉积物岩心的高积累率使其具有很好的时间分辨率。因此，有可能研究沉积231 Pa/230 Th对几个短期气候事件（如Heinrich事件）的响应。