• 责任者：Sha Shaoli (Yunnan Geological Survey ; Kunming 650051 ; China) ; Liu Xuelong
• 刊名：Journal of Stratigraphy
• 出版年：2013
• 卷期：37(3)
• 关键词：三叠纪 ; Triassic ; 地层划分 ; stratigraphic classification ; 云南 ; Yunnan Province
• 页码：p.343-348
• 图表：illus., 1 table, 12 refs.
• 分类号：1200
• issnNo：ISSN0253-4959
• isbnNo：CN32-1187/P

     Triassic strata are widely distributed in northwestern Yunnan, which can be divided into, from west to east, the Lancang, Lanping, and Jinsha River stratigraphic regions. In the Lanping stratigraphic region, Triassic strata consist of the Upper Triassic Waigucun, Sanhedong, Waluba, and Maichuqing groups, which are sporadically distributed as nappes or klippes unconformably overlying the upper Permian Yangbazhai Group and underlying the Middle Jurassic Yangiiang Formation. The Triassic strata in the Lanping stratigraphic region contain bivalves, ammonoids, gastropods, conodonts and plant fossils, and they are Carnian to Rhaetian in age. In the Jinsha River stratigraphic region, Triassic strata include the Middle Triassic Shanglan and Pangtiange groups, and the Upper Triassic Cuiyibi and Shizhongshan groups. They contain rich bivalves, braehiopods, ammonoids, foraminifera, conodont fossils, and concho-stracans. The Pangtiange and Cuiyibi groups contain bimodal volcanic rocks and yield radiometric ages of 224 Ma, 236 Ma, 238 Ma, 248±4.4 Ma, suggesting a Triassic age. It was previously thought that the Shanglan Group unconformably overlies the lower Permian Lazhuhe Group. Subsequent studies showed that the unconformity was a fault within the Shanlan group and the Lazhuhe Group does not exist. Al- though there are many similarities between the Lanping and Jinsha River stratigraphic regions, the differ- ences justify the usage of independent stratigraphic systems in these two regions.