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南段组是一套厚度巨大的砂岩与泥岩的互层沉积，沉积构造主要是块状层理、水平层理和少量的小型滑动变形构造、小型斜层理和粒序层理以及浪成波痕。砂岩粒度概率累积曲线显示牵引流与重力流的过渡特征，砂岩的Ｃ－Ｍ图显示重力流沉积特征。砂岩成分成熟度高（石英＞９０％），结构成熟度中等（杂质为０—１６％），有时出现沉积石英岩。砂岩和泥岩的地球化学特征表明是被动大陆边缘背景下的沉积。在南段组中新发现的Ｃｈｏｎｄｒｉｔｅｓｓｐ．，Ｓｃａｌａｒｉｔｕｂａｓｐ．，Ｐｈａｎｏｌｉｔｅｓｓｐ．３种遗迹化石和一些原地埋藏的浅海底栖双壳类化石等，则代表了一个深陆棚沉积环境。以上特征表明南段组是一套浪控三角洲前缘斜坡－深陆棚环境的近源片泛性（非扇模式）重力流和正常陆棚的复合沉积，并非深海复理石建造
The southern segment is a set of interbedded sediments of sandstone and mudstone of great thickness. The sedimentary structures are mainly massive bedding, horizontal bedding and a small number of small sliding deformation structures, small oblique bedding and sequence stratification, and waves into waves mark. The cumulative probability of sandstone granularity shows the transitional characteristics between the traction flow and the gravity flow, and the sandstone C-M diagram shows the gravity flow sedimentary characteristics. Sandstone has high maturity (quartz> 90%), medium maturity (0-16% impurities) and sometimes quartzite deposition. The geochemical characteristics of sandstone and mudstone indicate deposition in the passive continental margin. Chondritessp newly discovered in the southern section. Scalaritubasp. , Phanolitessp. Three kinds of trace fossils and some in-situ buried shallow benthic amphibious bivalve fossils represent a deep-shelf depositional environment. The above characteristics indicate that the southern segment is a set of composite deposition of near-source generalized (non-fan mode) gravity flow and normal continental shelf in a wave-controlled delta front-slope continental shelf environment and is not constructed of deep-sea flysch