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.

沿海地区被认为是受海平面上升影响最脆弱的环境之一，其地貌与水文的多样性使得相关研究极具复杂性。要厘清其演化规律，必先对当前的地貌-沉积（morpho-sedimentary）分布特征与作用过程进行精准刻画。本研究通过激光雷达（LiDAR）数据开展地貌解译，结合200份样品的粒度与地球化学分析，并辅以主成分分析（PCA）等统计工具进行后续解读，最终明确了法国诺曼底赛雷湾（Saire Bay）的沉积物输运模式。尽管该区域主要受潮流控制，但赛雷湾的原始地貌特征显示，其砂质潮滩上存在一种罕见的复杂环流系统。由潮流驱动的沉积陆海交换过程，并非通过北部的赛雷河网完成，而是发生在南部一条相对隐蔽的次级水道沿线。本研究结果可为深入理解海岸线演化提供重要基础。