中文摘要：

通过对长江口北支STG剖面沉积物粒度、环境磁学特征及有孔虫组合特征分析，发现该剖面沉积物以中粉砂和粗粉砂为主；磁性矿物以亚铁磁性矿物为主，不完整反铁磁性矿物含量较低；包含有3个有孔虫组合带。进一步分析，得出该剖面为潮滩沉积环境，并按自下而上顺序，可将其进一步划分出3个沉积层次，即层1→层3，层1为低潮滩沉积环境、层2为中潮滩沉积环境、层3为高潮滩沉积环境。反应潮流作用强弱的印蠡．tomineUanaraensis与Ammoniaconvexidorsa含量百分比，自层1→层3依次变小，反映该剖面潮流作用自层1→层3依次减弱。

英文摘要：

Through analsizing the characteristics of the sedimentary granularity, environmental magnetic and foraminiferal assemblages of the section plane STG, in the North Branch of Yangtze River estuary, found that the medium silt and coarse silt are the main component in the section plane STG; the main magnetic minerals are ferrimagnetic mineral, Whereas the incomplete antiferromagnetic mineral is low in sediments; there are also three foraminiferal assemblages in the section plane of STG. According to these parameters of the sedimentary granularity, environmental magnetic and foraminiferal assemblages, obtained that the section plane STG＇s sedimentary environment is tidal flat. According to the variation of these parameters in the vertical Section, this profile can be divided into three sedi- mentary layers, that is layerl→layer3. From layerl to layer3, the depositional environment is respectively low tidal flat, middling tidal flat, high tidal flat. The percentage of the Ammonia convexidorsa and Epistominella naraensis diminishs from layer 1→Layer3, which can response the change of the strength of tidal current weakened in turn.