晚第四纪钱塘江下切河谷体系层序地层特征  

Sequence Stratigraphy of the Qiantangjiang Incised-valley System Formed since the Last Glaciation

作　　者：张桂甲[1] 李从先[1] 

机构地区：[1]同济大学海洋地质开放实验室,上海200092

出　　处：《同济大学学报（自然科学版）》1998年第3期320-324,共5页Journal of Tongji University:Natural Science

基　　金：国家自然科学基金!49476280

摘　　要：钱塘江河口湾下切河谷体系为一强潮型的简单山前下切河谷体系，可分为两段：第一段从低海面时的下切河谷的口门至最大海侵时海相层深入内陆最远的地方．该段内沉积物向上分别为低位河床滞留沉积、早期海侵河流沉积、滨浅海沉积和高位河口湾及河流沉积第二段从第一段的内端至湖区界芦茨阜，缺失海相层和河口湾沉积，但受基面变化的影响，下切河谷体系缺乏湾顶三角洲、中央盆地、河口砂坝等地貌单元，因此，不可套用国外的模式来划分该下协河谷体系．Based on the straigraphic organization and the sedimentary characteristics, the tidal-dominated Qiantangjiang incised-valley system is soned into two sections: Section I(seaward) ranges from the mouth of the incised valley during the lowstand time (550km seaward away from the present coastline) to the landward limit of the marine facies during the maximum transgression (at the mountainous area near Hangzhou). The facies tract within the section is composed of fluvial-channel lag deposits during the loWstand time, retrogresive fluvial deposits during the earlier transgression, marine deposits and estuarine-fluvial depeits during the highstand time, upward respectively. Section Ⅱ (landward) ranges from the inner limit of the section Ⅰ to the present tidal limit (Lucifu), missing the marine and estuarine sediments. The fluvial depeition dominates at this section throughout its geological history, but the changes in sea leve at the estuarine meuth still influence the depositional processes. The intensity of the influence decreases upstream until the fluial system is controlled by the other factors, such as climate, tectonics, sediment supply, etc. No bayhead delta, cental basin and estuarine roth sandy barrier are available at the Qiantanagjiang incised-valley system, which are common at man wave-dominated estuarine incised-valley systems. Therefore, these geographic units and their sediments cannot be used to subdivide the tidal-dominated estuarine incised-valley systems.

关 键 词：钱塘江 下切河谷体系 层序地层 晚第四纪 

分 类 号：P736[天文地球—海洋地质]