A high-resolution study of Thorium isotopes in relation to the cycling of other trace elements in the Southern Ocean

钍同位素与南大洋其他微量元素循环关系的高分辨率研究

• 批准号: 47018667
• 负责人: Dr. Michiel Rutgers van der Loeff
• 金额: --
• 依托单位: Alfred-Wegener-Institut (AWI) Helmholtz-Zentrum für Polar- und Meeresforschung
• 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 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/47018667?language=en
• 关键词: resolution; study; Thorium; isotopes; relation

Natural radionuclides are powerful tracers for the rate of transport processes in the ocean. In the framework of GEOTRACES, a large international study on the cycling of trace elements and isotopes in the world ocean with extensive activities in the International Polar Year, we propose to determine the high-resolution distribution of Th isotopes, 231Pa and 227Ac along the Zero meridian and in the Drake Passage. The sampling has taken place in coordination with sampling of other trace elements by an international team of geochemists on an expedition with RV Polarstern. This joint sampling allows us to directly apply the information on particle dynamics (aggregation, disaggregation and particle sinking rates) and terrigenous input that we will obtain from the distribution of thorium isotopes and 231Pa, to the transport of other tracers. Similarly, we will be able to confront the results on water mass ventilation and upwelling, as we will derive from 230Th/231Pa and 227Ac distributions, with hydrographic data and the conclusions drawn from other tracers described in parallel proposals (Nd/Hf isotopes; freons and He isotopes). The data will be interpreted along with other tracer data in (inverse) GCM models. We expect that this approach will improve our ability to use a set of tracers as more reliable proxies for past ocean climate.

天然放射性核素是海洋中迁移过程速率的强有力示踪剂。GEOTRACES是一个大型的国际海洋微量元素和同位素循环研究项目，在国际极年开展了广泛的活动，在该项目的框架内，我们建议确定Th同位素、231 Pa和227 Ac沿着零子午线和德雷克海峡的高分辨率分布。这次取样是与一个国际地球化学家小组与北极星号考察队一起进行的其他微量元素取样协调进行的。这种联合采样使我们能够直接应用粒子动力学（聚集，解聚和粒子下沉率）和陆源输入，我们将获得从钍同位素和231帕的分布，其他示踪剂的运输信息。同样，我们将能够面对水团通风和上升流的结果，因为我们将来自230 Th/231 Pa和227 Ac分布，水文数据和平行建议中描述的其他示踪剂（Nd/Hf同位素;氟里昂和He同位素）得出的结论。这些数据将与（逆）GCM模型中的其他示踪剂数据一起沿着解释。我们希望这种方法将提高我们使用一组示踪剂作为过去海洋气候更可靠的代理的能力。