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路径。南极冷底水（AABW）作为西部边界流向北流过该盆地，北大西洋深水（NADW）作为西部边界流向南流过该盆地。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，例如德雷克通道的开放或里约热内卢大隆起/沃尔维斯山脊的火山流的广泛就位。水团形成了沉积物漂移，记录了水流的路径和强度。对漂移发展的及时识别、详细分析和绘图将有助于揭示水团的演变。反过来，这将导致形成期间的气候条件的信息。到目前为止，只调查了阿根廷盆地中部的漂移（例如Zapiola漂移）。我们将集中在大陆边缘，研究长期（始新世到全新世）洋流与沉积物输入的相互作用。阿根廷盆地是南大西洋四大盆地之一。它在早白垩纪时期开放（Hinz et al., 1999），因此建立了一个长期但高分辨率的海洋气候条件记录。因此，拟议的项目理想地解决了研究目标(a)大陆边缘和陆架区域的结构和形态，(b)大西洋盆地形态对建立近代和古海洋环流模式和气候反馈的影响，以及(c)在优先计划的研究重点D“沉积过程和流体系统”中制定的陆地和近海侵蚀和沉积过程。这里提出的项目进一步将构造重建与气候/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.