Abstract Past major changes in sea level have had a significant influence on global- and shelf sea tidal dynamics. Some of these changes are preserved in sedimentary records from the shelf seas, and so appropriate proxy data have the potential to constrain tidal model outputs over the recent geological past. Tidal models which simulate the evolution of tide-dependent parameters over geological timescales are fundamental to understanding the response of the tides to sea-level rise and climate change. This study explores a potential new sedimentary proxy for validating past shelf sea tidal dynamics, interrogating the relationship between tidally-modulated bed shear stress and seabed sediment grain size at discrete sediment core locations over the northwest European shelf seas. Radiocarbon-dated sediment grain size profiles were generated for four British Geological Survey UK shelf sediment vibrocores, spanning a range of physical environments. Changes in observed sediment grain size through time were compared with simulated changes in tidal-induced bed shear through time, using temporal and spatial outputs from the most recently developed palaeotidal model of the Northwest European shelf seas. Although a positive correlation between observed grain size and simulated bed shear stress was observed at three of the four sediment cores sites, no robust relationship could be quantified. The palaeotidal model output failed to resolve the details of the actual sediment dynamics, since only tidal-induced bed shear stresses were considered. Wave processes were neglected, and the model was not sensitive enough to constrain simulated past tidal conditions at point locations; rather it is suitable for examining general trends. There remains a need to develop new proxies for past shelf sea hydrodynamic conditions which can be used to constrain numerical model output of tidal currents at regional scales.

中文翻译：

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使用海底沉积物粒度作为潮汐流的代理来约束陆架海潮模型的挑战

摘要 过去海平面的重大变化对全球和陆架海潮动力学产生了重大影响。其中一些变化保存在陆架海的沉积记录中，因此适当的代理数据有可能限制最近地质过去的潮汐模型输出。潮汐模型模拟潮汐相关参数在地质时间尺度上的演变，对于了解潮汐对海平面上升和气候变化的响应至关重要。本研究探索了一种潜在的新沉积替代物，用于验证过去的陆架海潮汐动力学，探讨了在欧洲西北部陆架海上空离散沉积物核心位置的潮汐调制床剪切应力与海底沉积物粒度之间的关系。为四个英国地质调查局英国陆架沉积物振动核生成放射性碳测年沉积物粒度剖面，跨越一系列物理环境。使用来自欧洲西北部陆架海最近开发的古潮汐模型的时间和空间输出，将观察到的沉积物粒度随时间的变化与潮汐引起的床剪切随时间的模拟变化进行比较。尽管在四个沉积物核心站点中的三个站点观察到观察到的粒度与模拟床剪切应力之间存在正相关，但无法量化稳健的关系。古潮汐模型输出未能解决实际沉积物动力学的细节，因为只考虑了潮汐引起的床剪切应力。波浪过程被忽略，并且该模型不够灵敏，无法在点位置限制模拟的过去潮汐条件；相反，它适用于检查总体趋势。仍然需要为过去的大陆架海洋水动力条件开发新的代理，可用于在区域尺度上约束潮汐流的数值模型输出。