青藏高原南羌塘盆地西部中二叠统龙格组地层的研究

Research on the Middle Permian Longge formation in western part of the south Qiangtang Basin, Qianghai-Xizang(Tibet),China

龙格组为青藏高原南羌塘盆地西部晚古生代地层,本次工作对其岩石组合、古生物面貌、沉积环境、层序特征等进行了详细研究,将龙格组进一步划分为三个段,初步认定一段主要形成于开阔台地亚相、二段形成于局限台地和潮坪亚相、三段形成于潮间带-潮上带微相,从下往上反映海水逐渐变浅过程。依据地层中出露的蜓类、腕足类、腹足类、双壳类和珊瑚等海相化石的详细鉴定结果,认定龙格组形成于中二叠世栖霞期-茅口期。此研究可为深入探讨南羌塘盆地西部古生代大地构造背景及晚古生代盆地边界、盆地属性等研究提供了重要的基础地质资料。

The Middle Permian Longge formation is located in the west-south Qiangtang basin.The investigations of mineral sparagenesis, paleontological features, sedimentary characterization and remote sensing data are carried out in detail. The Longge formation is divided into three members from the bottom up. The sedimentary environments of the Longge formation were open platform, restricted platform, and intertidal to supralittoral zone, respectively, which indicated the seawater became shallow. The marine fossils are well developed in the Longge formation, such asfusulinida, brachiopods, gastropod, bivalves andcorals, suggesting the Longge formation formed in Permian Qixia Stage to Maokou Stage. This research provides the basic geological data which could improve the studies of the tectonic setting in southern Qiangtang basin during Paleozoic period.