扬子浅滩南部地形地貌精细研究及成因机制分析

Based on the new discovers on the continental shelf outside Yangtze River estuary during "908" investigation, we choose the southern portion of the Yangtze Shoal as the study area of our proposal. The study aims to establish a 3D topography model based on high resolution multi-beam echo-sounding system and high density side scan sonar system surveys on morphologic features and development degree of the active submarine micro-topography bodies. At the same time, it will analyze the main control factor that has affected the geomorphic evolution since the Late Pleistocene, and investigate the vertical distribution pattern and material sources of the shallow sediment layer, by the means of the higher resolution information extracted from the surface and troughs of the Yangtze Shoal, combing with the sedimentary columnar sampling and the single seismic surveys. The bottom current and sediment transport are simulated to investigate the effect of the modern hydrodynamic mechanism on the shaping process of submarine geomorphology. The study is further to elucidate the formation mechanism of the Yangtze shoal, and to set up shoal and its micro-topography evolutionary pattern since the late Pleistocene.

基于"908"专项对长江口外陆架区调查得出的地貌新发现，本项目拟选择扬子浅滩南部作为研究区，利用高精度多波束测深系统和高密度侧扫声呐系统对该区的地形地貌特征和海底表面微地貌体发育状况进行研究，建立三维地形地貌模型。进一步选取浅滩滩面和沟槽处进行高分辨的精细地形地貌信息提取，并通过沉积柱状采样和单道地震调查等综合手段，研究该区近表层沉积物垂向分布格局和物质来源，分析影响晚更新世以来地貌演化过程主控因素；模拟研究区海底底层流场和输沙量，分析现代水动力对海底地貌塑造的影响程度。研究扬子浅滩形成机理，建立晚更新世以来扬子浅滩及其微地貌的演化模式。

本项目基于“908”专项对长江口外陆架区调查得出的地貌新发现，利用高精度多波束测深系统、侧扫声呐和单道地震系统，精细研究扬子浅滩南部沟槽地貌特征和海底表面微地貌体发育状况，结合沉积地球化学数据，构建研究区近表层沉积物垂向分布格局和物质来源，分析影响晚更新世以来地貌演化过程主控因素；模拟研究区海底底层流场和输沙量，分析现代水动力对海底地貌塑造的影响程度。研究扬子浅滩形成机理，建立晚更新世以来扬子浅滩及其微地貌的演化模式。