Reconstruction of palaeo-currents via the investigation of sediment drifts

阿根廷盆地是全球传送带中的一条重要通道。南极冷底水(AABW)为通过该盆地的西边界流，北大西洋深水(NADW)为西边界流。南极中间水(AAIW)也沿着阿根廷大陆边缘向北移动(The_Open_University，1999)。因此，阿根廷大陆边缘的沉积序列代表了这些水团的演化及其变化(路径、物理和化学性质)的重要档案，例如，它们与板块构造事件有关，如德雷克海峡的打开或火山在里奥格兰德隆起/瓦尔维斯山脊的广泛侵位。水团形成了泥沙漂流，记录了水流的路径和强度。及时识别并详细分析和绘制漂移发展图将有助于揭示水团的演化。这反过来将导致关于形成期间气候条件的信息。到目前为止，只对阿根廷盆地中部的漂流(如Zapiola漂移)进行了调查。我们将集中于大陆边缘，研究洋流与沉积物输入的长期(始新世至全新世)相互作用。阿根廷盆地是南大西洋的四大盆地之一。它开放于白垩纪早期(Hinz等人，1999)，因此建立了长期但高分辨率的海洋气候条件记录。因此，拟议项目很好地解决了研究目标：(A)大陆边缘和陆架区的结构和形态，(B)大西洋盆地形态对建立现代和古海洋环流模式和气候反馈的影响，以及(C)在优先方案的研究重点D“沉积过程和流体系统”范围内形成的海岸和近海侵蚀和沉积过程。这里介绍的项目进一步将构造重建和气候/洋流模拟联系起来。

The Argentine Basin represents an important path within the global conveyor belt. Cold Antarctic Bottom Water (AABW) takes a northward path as a western boundary current through this basin, and North Atlantic Deep Water (NADW) takes a southern route as a western boundary current. Antarctic Intermediate Water (AAIW) also sets towards the north along the Argentine continental margin (The_Open_University, 1999). The sedimentary sequences at the Argentine continental margin hence represent an important archive of the evolution of those water masses and their modifications (path, physical and chemical properties) e.g. they relate to plate tectonic events such as the opening of the Drake passage or the extensive emplacement of volcanic flows at the Rio Grande Rise/Walvis Ridge. The water masses formed sediment drifts, which document path and intensity of the flow. An identification and detailed analysis and mapping of the drift development in time will shed light on the evolution of the water masses. This in turn will lead to information on the climatic condition during formation. Up to now only the drifts in the central Argentine Basin (e.g. Zapiola Drift) have been investigated. We will concentrate on the continental margin and study long-term (Eocene to Holocene) interaction of the currents with sediment input. The Argentine Basin forms one of the four major basins of the South Atlantic. It opened in Early Cretaceous times (Hinz et al., 1999) and hence built up a long term but high resolution record of the oceanographic-climatic conditions. The proposed project thus ideally tackles the research goals (a) Structure and morphology of the continental margins and shelf areas, (b) The effects of the basin morphology of the Atlantic on the establishment of recent and palaeo-oceanic circulation patterns and climatefeedback, and (c) Erosion and sedimentation processes on- and offshore formulated within the research focus D ‘Sedimentary processes and fluid systems’ of the priority program. The project presented here further links tectonic reconstructions and climate/ocean current simulations.