长江三角洲亚三角洲地层结构对比

依据对江苏省泰兴市黄桥镇钻孔和海门市钻孔、上海长兴岛钻孔地层岩心沉积特征的研究,讨论了冰后期以来长江三角洲河口地区的层序地层。研究表明,沿古河谷纵剖面各河段地层中沉积相组合关系有明显区别。在古河谷下端地区,下切河谷充填层序自下而上由河流相、河口湾相、浅海相和三角洲相组成,沉积相组合最完整。在古河谷上端地区,由于河口湾在海侵发生时存在着涌潮作用,因此,河漫滩泥质沉积层顶部的冲刷面被确定为最大海泛面,其上覆稳定的河口砂体;浅海相和河口湾相沉积在该区域变薄直至尖灭;层序顶部由中潮坪突变为高潮坪,最终形成泛滥平原。这意味着,原先确定的自西向东的长江三角洲的几个亚三角洲或河口砂体沉积,并非都具有向上变粗的三角洲层序。文中报道的3个钻孔,揭露了冰后期长江三角洲完整的下切河谷充填层序。河口湾顶不具备三角洲层序的地区应称为滨海平原。

Correlation of stratigraphic architecture of sub-deltas of Changjiang River Delta

On the basis of sedimentologic analyses and stratigraphic correlation of three drilling holes located at Huangqiao town of Taixing city, Haimen city of Jiangsu Province and Changxing island of Shanghai respectively,the sedimentary sequence in estuary of the Changjiang River Delta since post-glacial stage is discussed. The research shows that the sedimentary facies assemblages at different river section differ with each other along the longitudinal profile of the river valley.At the lower end area of the pal...