钱塘江南岸ＳＥ２孔晚第四纪以来沉积物粒度特征及环境演化

利用钱塘江南岸萧山地区SE2孔的粒度资料，分析了粒度参数、频率分布曲线和概率累积曲线的 特征，并结合沉积物的岩性、沉积构造和有孔虫的分布特点，探讨了该区自晚第四纪以来的沉积环境演化。结 果表明，晚第四纪以来，钱塘江南岸地区依次接受了河床相、河漫滩相、潮坪相、近岸浅海相和河口湾相5种 沉积。河床相沉积物以砂砾为主，粒度参数变化较大，概率分布曲线为3段式，频率分布曲线为不对称的双峰 式，主要发育块状层理，生物化石稀少。河漫滩相以细砂、粉砂级沉积物为主，频率分布曲线为单峰式，富含 生物壳体碎屑和植物根茎。潮坪相沉积物表现为粉砂和黏土互层沉积，粒度参数变化频繁，频率分布曲线多为 双峰式，韵律层理发育。近岸浅海相沉积物主要为淤泥质黏土，粒度参数稳定，概率分布曲线为2段式，以悬 浮组分为主，频率分布曲线为单峰式，有孔虫含量丰富。河口湾相沉积物以粉砂和细砂组成的韵律性沉积为主， 粒度参数富于变化，概率分布曲线为3段式，频率分布曲线为双峰式。

Sediments grain-size characteristics and environmental evolution of Core SE2 in southern bank of Qiangtang River since the Late Quaternary

Data of grain-size,lithology,sedimentary structures and paleontology of the Core SE2 in southern bank of the Qiangtang River,are used to interpret the environmental evolution in this area.The study suggests that there are five types of deposits in Core SE2 from bottom to top:Fluvial channel,floodplain,tidal flat,shallow marine,and estuary.Fluvial channel sediments which consist of sandy gravel have a wide range of grain-size parameters distribution,showing three parts in probability accumulation curves and ...