Sedimentary hydrodynamics of a sandy bay under macrotidal conditions (Saire Bay, France)

Identified as one of the most vulnerable environment to the impacts of sea-level rise, the morphological and hydrological diversity of coastal areas complicates their study. To understand their evolution, it is essential to characterize their current morpho-sedimentary distributions and processes. Morphologic interpretation, from LiDAR data, coupled with grain-size and geochemical analyses of 200 samples, subsequently interpreted with statistical tools (PCA), allow us to determine the pattern of sedimentary transport of Saire Bay (Normandy, France).Even if the area is mainly dominated by tidal currents, the original morphology of Saire Bay highlights an uncommon complex circulation on a sandy tidal flat. Sedimentary land-sea exchanges, induced by tidal current, do not occur through the river Saire network in the north, but in south, along a less apparent secondary channel. Results provide an essential base to better understand the evolution of the coastline.

沿海区域被视作受海平面上升影响最为脆弱的环境之一，其地貌与水文的多样性使得相关研究复杂度显著提升。为厘清该类区域的演化规律，对其当前的地貌-沉积分布特征与过程进行精准刻画至关重要。本研究结合激光雷达（LiDAR）数据开展地貌解译，对200份样品实施粒度与地球化学分析，并借助主成分分析（PCA）等统计工具开展后续解读，最终明确了法国诺曼底赛雷湾（Saire Bay）的沉积物输运格局。尽管该区域整体以潮流作用为主导，赛雷湾的原生地貌特征却揭示出砂质潮间带存在一种罕见的复杂环流模式。由潮流驱动的海陆沉积物质交换，并未通过北部的赛雷河网完成，而是沿南部一条不甚明显的次级水道进行。本研究结果可为深入理解海岸带演化提供重要基础支撑。