Lemengou Fm
(31), early-Middle Permian
Type Locality and Naming
The type section is located in the Zhongshigong area to the southwest of the Xiahuancang region, Tianjun County, Qinghai Province. It was named by Liu Guangcai in 1980, and was issued publicly in 1984. Lower formation in the Bayinhe Gr.
Lithology and Thickness
Coarse clastics and Limestone. Purplish-red and dark-grey thick-bedded quartz-conglomerate, medium- and fine-grained quartz-sandstone and siltstone, intercalated with thick-bedded bio-limestone. Thickness is 263 m.
Relationships and Distribution
Lower contact
Unconformable contact with the underlying Caledonian (Silurian) pink porphyritic granite.
Upper contact
Conformable and transitional to the Caodigou Fm.
Regional extent
Distributed in the area extending from the Zhongshigong area to the Shulenanshan Mts. in the Tianjun County, and it may probably be missing in the area of the Riyue Mt. In the Tuolongliang area to the south of the Buha River the formation is composed already of grey dolomite.
GeoJSON
Fossils
Yields Fusulinida represented by Staffella moellerana and Misellina; Corals represented by Protomichelinia aff. multiabulata; and Bryozoan represented by the Fenestella qinghaiconstans-Fistulipora megastoma assemblage, etc.
Age
Depositional setting
It is interpreted as shallow-sea deposits formed at the early stage of marine transgression.
Additional Information