苏北金湖凹陷北部,包括三个次一级构造单元,即三河次凹陷、刘庄构造带和唐港构造带(图1)。该区处于东台坳陷与建湖隆起两大构造单元的过渡地带,新生代沉积变化较大,相变与地层缺失现象错综复杂。本文所研究的早第三纪晚期—晚第三纪沉积,即三垛组二段(简称“垛二段”)—盐城组二段(简称“盐二段”)尤其如此。 The northern Jinhu depression, northern Jiangsu, consists of three sub-tectonic units, the Sanhe Sag, Liuzhuang tectonic belt and Tanggang structural belt (Figure 1). This area is located in the transitional zone between the two major structural units of Dongtai Depression and Jianhu Uplift. The sediments of Cenozoic vary greatly and the phenomena of phase transition and formation loss are complex. The study of the late Tertiary-Late Tertiary sediments studied in this paper is especially the second member of Yancheng Formation (the second member of Yancheng Formation).