Modeling the Deposition System Evolution of Accreting Tidal Flats: A Case Study from the Coastal Plain of Central Jiangsu, China

摘要

The evolution of an accreting tidal flat is controlled mainly by tidally induced mud and sand transport. To understand the dynamic processes related to the evolution patterns, a model, taking into account the mud and sand transport associated with spring neap tidal cycles, is used to simulate the formation of the deposition system of accreting tidal flats on the coastal plain of central Jiangsu, China. Based on the model output and a comparison with the observations, the following conclusions are derived. First, the vertically fining upward trend of sediment grain size in the deposition system of the tidal flat has been reproduced by the modeling. Second, the thickness of the mud layer (i.e. the upper part of the tidal flat deposit, where the mud content is more than 50%) in this deposition system is mainly determined by sediment supply. Abundant sediment supply to the tidal flat will result in a high sedimentation rate, rapid shoreline progradation, and a large volume of mud deposit but small mud layer thickness. Finally, no positive correlation is found between the thickness of a mud layer and the tidal range based on an analysis of the data set obtained from a number of muddy coasts in the world. However, a large tidal range may enhance the proportion of sand in the deposition system.