Long-term evolution of late Pliocene to mid-Pleistocene bottom current regime in response to intermediate water circulation in the NE-Atlantic

拟议的项目将详细说明上新世-更新世古水流强度的长期历史，以应对北大西洋漂流沉积物产生NADW的主要地点之一附近的深水和中层水的形成。最近在从底流搬运的细沉积物中分离出淤泥大小的冰筏碎片方面取得的进展将用于建立可靠的古水流记录，从而确定在重大环境变化期间水流强度的变化和演变。细砂和粉砂部分的详细粒度分析将为端元建模提供基础，端元建模是对不同粒度但来源不同的未混合沉积物的一种统计方法。通过区分泥沙大小的冰筏偏见从底层电流沉积物运输，我们将能够整合的结果，从高纬度海洋上新世/更新世深水形成和古水流强度重建地区进一步下游的温盐环流回路，更好地了解这个全球系统的物理流态。

The proposed project will elaborate a long-term history of Pliocene-Pleistocene palaeocurrent strength in response to deep and intermediate water formation close to one of the main locations of NADW production from drift sediments in the North Atlantic. Recent progress in unravelling ice-rafted debris of silt size from bottom current transported fine sediments will be used to establish a reliable palaeocurrent record, and thus the variability and evolution in current strength during times of significant environmental changes. Detailed grain-size analysis of the fine sand and silt fraction will provide the base for the end-member modelling, a mathematical-statistical approach to unmix sediments of distinct size fractions but different in their origin. By the differentiation of silt-sized ice-rafted bias from bottom current sediment transport, we will be able to integrate the results from the high-latitude oceans in Pliocene/Pleistocene deep-water formation and palaeocurrent strength reconstructions regions further downstream in the thermohaline circulation loop for a better insight into the physical flow regime of this global system.