珠江口伶仃洋海底沉积

在前人工作的基础上,利用2003—2005年广州海洋地质调查局1∶10万《珠江三角洲近岸海洋地质环境与地质灾害调查》项目的实测资料,综合分析了伶仃洋海底的沉积特征,认为伶仃洋表层沉积物类型有:砂、黏土质砂、砂-粉砂-黏土、砂质黏土、黏土质粉砂、粉砂质黏土等6种类型。伶仃洋晚更新世以来的海底地层主要有两套:层A为全新世冰后期海侵以来逐渐堆积而成的沉积物,钻孔揭示的沉积物类型主要为黏土质砂和砂—粉砂—粉砂质黏土;层B为一套晚更新世的黏土质粉砂、细砂—粗砂(含砾)、粉砂质黏土—黏土,以陆相沉积和剥蚀为主,局部为海陆交互相沉积,其下地层则为基岩风化物和基岩。

THE CHARACTERISTICS ANALYSIS OF SEA BOTTOM DEPOSIT IN LINGDINGYANG BAY OF THE PEARL RIVER ESTUARY

The geo-environment along the coast of the Pearl River estuary is very sensitive as the area lies in the interacting zone between ocean and land.It will be very useful for sustainable development of regional exploitation and construction if understanding the characteristics of sea bottom deposit in Lingdingyang Bay.Based on the fore-researches of shoals,troughs,seabed topography and sediments etc,Guangzhou Marine Geological Survey(GMGS)carried out the project(1:100 000)of marine geo-environment and geo-hazards survey in the Pearl River delta between 2003 and 2005,and then analyzed the deposit characteristics of Lingdingyang.After the integration of the data of geophysics,seabed sediments and strata from soil samplings and drilling cores,the result is that the seabed sediments of Lingdingyang have 6 types:sand,silty sand,sand-silt-clay,sandy clay,clayey silt,and silty clay.The sea bottom deposits of Lingdingyang since late Pleistocene consist of two stratal groups.Stratal A is the transgressive sediments since Holocene.The sediments are mainly silty sand and sand-silt-silty clay in accordance with drilling cores.Stratal B is mainly the sediments of terrestrial deposit and denudation,with some as marine-terrigenous facies.The sediments are mainly clayey silt,fine sand-coarse sand with gravel and silty clay-clay since late Pleistocene.It is the demorphism of rock and bedrock below stratal B.