Transport, Removal and Accumulation of sediments Numerically Simulated for Paleo-Oceans and Reconstructed from cores of The Eirik Drift (TRANSPORTED)

古海洋沉积物的运输、清除和堆积数值模拟以及埃里克漂流岩心重建（运输）

• 批准号: 387249925
• 负责人: Dr. Jan Saynisch-Wagner, since 11/2018
• 金额: --
• 依托单位: Sektion 1.3: Erdsystem-Modellierung
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/387249925?language=en
• 关键词: Transport; Removal; Accumulation; sediments; Numerically

The Western Boundary Undercurrent (WBUC) is a crucial component of the global ocean conveyor belt and is driven by Deep Water Formation (DWF) in the Greenland, Labrador, Norwegian and Iceland Seas. Seismic profiles imaging the Eirik Drift indicate a high variability in velocities and flowpath of the WBUC since the early Miocene and provide indications on the area of DWF from the Miocene to present day. We aim at identifying the mechanisms involved in shifts of DWF sites and redirection of the WBUC. Grain size data is available for ODP Leg 105 Site 646 and IODP Expedition 303 Sites U1305-1307 drilled at the Eirik Drift (iodp.tamu.edu). The distinction into clay (less than 0.004 mm), silt (0.004-0.063 mm), and sand (more than 0.063 mm) is sufficient to deduce resolvable velocities of the WBUC for the different periods. Three-dimensional velocities and sediment transports will be simulated with the Regional Ocean Modelling System (ROMS). ROMS will be localized to the North Atlantic and therefore yield detailed information about DWF sites and ocean currents. Seismic profiles collected in the area of the Eirik Drift (Uenzelmann-Neben (2013)) provide horizon depths, thicknesses of sedimentary units, and location and orientation of depocentres. In combination with the grain size data ground truth data is provided for the sediment transport patterns modelled by ROMS. With the numerical approach we can single out or neglect effects and thereby perform sensitivity studies regarding the influence of changing climate conditions and tectonic configurations on deep ocean currents and sediment transport. Müller-Michaelis and Uenzelmann-Neben (2014) attributed variable sediment deposition in the Eirik Drift to changes in strength and pathway of the WBUC, which originated in alternating sites of DWF. This hypothesis can be tested by the regional simulations and the climatic conditions responsible for the changes in DWF sites can be identified. The pathway of the WBUC is additionally affected by tectonic events, e.g., subsidence of the Greenland-Scotland Ridge or closing of the Central American Seaway. The influence of tectonic alterations on strength and pathway of the WBUC as well as on sedimentation rate and grain size will be studied in this project. We will, hence, link modifications in sedimentation rates and grain sizes recorded in the cores from Sites 646 and U1305-1307 to climatic and tectonically forced alterations of flowpaths and velocities of the WBUC.

西界潜流（WBUC）是全球海洋传送带的重要组成部分，由格陵兰海、拉布拉多海、挪威海和冰岛海的深水地层（DWF）驱动。Eirik漂移的地震剖面成像表明，中新世早期以来，WBUC的速度和流动路径具有很高的变异性，并为中新世至今的DWF面积提供了指示。我们的目标是确定DWF站点转移和WBUC重定向所涉及的机制。粒度数据可用于ODP Leg 105 Site 646和IODP Expedition 303 Sites U1305-1307在Eirik Drift钻探（iodp.tamu.edu）。将其分为粘土（小于0.004 mm）、粉砂（0.004-0.063 mm）和砂（大于0.063 mm），足以推断出不同时期WBUC的可分辨速度。三维速度和泥沙输运将用区域海洋模拟系统（ROMS）模拟。ROMS将局限于北大西洋，因此可获得有关DWF地点和洋流的详细信息。在erik漂移区域收集的地震剖面（Uenzelmann-Neben(2013)）提供了层位深度、沉积单元厚度以及沉积中心的位置和方向。结合粒度数据，为ROMS模拟的输沙模式提供了地面真值数据。利用数值方法，我们可以挑出或忽略影响，从而对气候条件和构造构型变化对深海洋流和沉积物运移的影响进行敏感性研究。m<s:1> ller- michaelis和Uenzelmann-Neben（2014）将Eirik漂移中泥沙沉积的变化归因于WBUC强度和路径的变化，这源于DWF位置的交替。这一假设可以通过区域模拟来验证，并可以确定导致DWF站点变化的气候条件。WBUC的路径还受到构造事件的影响，例如格陵兰-苏格兰海脊的下沉或中美洲海道的关闭。本项目将研究构造蚀变对WBUC强度、路径以及沉积速率和粒度的影响。因此，我们将把646站点和U1305-1307站点的岩心中记录的沉积速率和粒度的变化与气候和构造强迫的WBUC流动路径和速度的变化联系起来。