Millennial-scale changes in position and intensity of the Deep Western Boundary Current (DWBC) during the last glacial period

末次冰期深西部边界流（DWBC）位置和强度的千年尺度变化

• 批准号: 5434877
• 负责人: Professor Dr. Gerold Wefer
• 金额: --
• 依托单位: Zentrum für Marine Umweltwissenschaften (MARUM)
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2004
• 资助国家: 德国
• 起止时间: 2003-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5434877?language=en
• 关键词: Millennial; scale; changes; position; intensity

We propose to study terrigenous and biogenic fluxes on the Blake-Bahama Outer Ridge system (Western North Atlantic) at millennial scale resolution to monitor changes of the Deep Western Boundary Current (DWBC) through the last glacial period (10-70 kyr) in 3 dimensions. The investigation will be based on cm-resolution X-ray fluorescence (XRF) measurements of element intensities (Ca, Fe, Ti, Al, Si, Ba) on ODP Sites 1055 to 1062 drilled during Leg 172. Combined with detailed age models and calibration measurements on discrete samples the XRF records will result in millennial-scale resolution time series of biogenic and terrigenous sediment accumulation. A synthesis of these sediment fluxes along a depth transect (2164 to 4775 m water depth) on the Blake Outer Ridge (Sites 1055 to 1061) will allow to infer changes in the position of deep and intermediate water flow and thus be a test for model results that suggest that the prominent climate cycles of the last glacial period known als Dansgaard/Oeschger and Heinrich events were linked to three modes of North Atlantic Deep Water (NADW) formation (modern-, glacial-, and Heinrich mode). The relative current intensity of the DWBC will be derived from a detailed study of mud wave migration on the Bahama Outer Ridge (Site 1062). Furthermore elemental ratios (e.g. Al/Ti, Ba/Ti) will help to explore millennial changes in terrigenous provenance and biogenic productivity in the western North Atlantic.

我们建议以千年尺度分辨率研究布莱克-巴哈马外脊系统（北大西洋西部）的陆源和生物通量，以监测 3 年内末次冰河期（10-70 kyr）深西边界流（DWBC）的变化。方面。该调查将基于在第 172 段期间钻探的 ODP 站点 1055 至 1062 上元素强度（Ca、Fe、Ti、Al、Si、Ba）的厘米分辨率 X 射线荧光 (XRF) 测量。结合详细的年龄模型和对离散样本的校准测量，XRF 记录将产生生物和陆源沉积物积累的千年尺度分辨率时间序列。沿着布莱克外山脊（地点 1055 至 1061）的深度横断面（水深 2164 至 4775 m）合成这些沉积物通量将有助于推断深层和中层水流位置的变化，从而成为模型的测试结果表明，最后一个冰期的突出气候周期（称为 Dansgaard/Oeschger 和 Heinrich 事件）与北大西洋深水的三种模式有关(NADW) 形成（现代模式、冰川模式和海因里希模式）。 DWBC 的相对水流强度将通过对巴哈马外海脊（1062 号地点）泥浆波迁移的详细研究得出。此外，元素比率（例如 Al/Ti、Ba/Ti）将有助于探索北大西洋西部陆源来源和生物生产力的千年变化。