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.

我们建议研究陆源和生物通量的布莱克-巴哈马外脊系统（西北大西洋）在千年尺度的分辨率监测变化的深西部边界流（DWBC）通过末次冰期（10-70 kyr）在3个维度。调查将基于172航次期间钻探的ODP站点1055至1062的元素强度（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离散样品的校准测量，XRF记录将导致生物和陆源沉积物积累的千年尺度分辨率时间序列。沿深度剖面沿着沉积通量的综合（水深2 164至4 775米）（地点1055至1061）将允许推断深层和中层水流位置的变化，从而对模型结果进行测试，这些结果表明，已知的末次冰期的主要气候循环是Dansgaard/Oeschger和Heinrich事件与北大西洋深水（NADW）形成的三种模式（现代模式，冰川模式和Heinrich模式）有关。DWBC的相对海流强度将从巴哈马外脊（1062号站点）泥波迁移的详细研究中得出。此外，元素比（如Al/Ti，Ba/Ti）将有助于探索在北大西洋西部的陆源和生物生产力的千年变化。