Geometric modeling of Holocene large-river delta growth patterns,as constrained by environmental settings

作者：Gaocong LI,Qiong XIA,Yaping WANG,Zhiqiang LI,Shu GAO

摘要：Topographic/bathymetric conditions of the continental shelf can significantly influence the long-term growth of river deltas.In particular,these conditions constrain the accommodation space for sedimentation in the deltaic areas.In this study,we use a conceptual geometric model to evaluate the role played by this factor,on the basis of the principle of mass conservation.The Ganges-Brahmaputra,Mekong and Nile deltas are examined as three typical examples,in terms of their different original seabed morphologies.The control variate method is applied to eliminate the effect of the difference in model input variables.The results show that,assuming a constant sediment load,the delta growth rate will decrease with time;a higher value of the original seabed slope leads to a lower shoreline progradation rate for the subaerial delta and a higher growth rate for the subaqueous delta.Thus,the original seabed morphology represented by slope is a critical factor affecting the evolution of Holocene large-river deltas.These results explain the interrelationships between sediment load,deltaic plain area,and the original seabed slopes for the 27 large-river deltas worldwide,located in the middle/low latitudes,with different tectonic backgrounds.In the future,the conceptual geometric model may be combined with sediment dynamic modeling to identify more details of the evolution of these deltas.

发文机构：Department of Marine Technology Southern Marine Science and Engineering Guangdong Laboratory（Zhuhai） Marine Resources Big Data Center of South China Sea State Key Laboratory for Estuarine and Coastal Research

关键词：Large-riverdeltasOriginaltopography/bathymetryGeometricmodelingGrowthgeometryHOLOCENE

分类号： P73[天文地球—海洋科学]