渤海沿岸临清坳陷堂古5井中三叠统轮藻化石与地层划分对比

在临清坳陷堂古5井发现轮藻化石Stenochara和Stellatochara两属7种，证实该区存在三叠世地层。根据地层层序、岩石地层特征和区域地质资料分析，该区亦应存在下三叠统，并建议参照区域方案将该区中、下三叠统红层划分为刘家沟组、和尚沟组和二马营组。

Middle Triassic charophytes from Hole Tanggu 5 and the Subdivission and correlation of the Lower Middle Triassic red beds in Lingqing depression, Bohai Sea Coast

The fossil Charophytes reported here were collected from the Lower -Middle Triassic of the Tanggu-5 hole in the Lingqing Depression, Bohai sea coast.They contain 7 species in 2 genera (Stenochara and Stellatochara). This fossil assemblage is similar to those found from the middle Triassic Ermaying Formation in Dengfeng,Dancheng, Huaiyang, Henan province and Yaoxian,Tongchuan,Hancheng, Shanxi province, and may be correlated with the middle Triassic Charophyte assemblages from South Sweden, Germany and Russia. Therefore,the Charophyte-bearing beds in hole Tanggu-5 should be assigned to the Middle Triassic. According to the regional geological information of North China and the stratigraphic sequences and their sediment features of hole Tanggu-5, not only the middle Triassic but also the lower Triassic should be present in the Lingqing Depression. They are all red beds of sandstones and mudstones with high resistivity, corresponding with the Lower Trissic Liujiagou Formation,Heshanggou Formation and Middle Triassic Ermaying Formation ,which widely spread from the southwest to the centre of the North China Platform.