Raggyorcaka Fm
Type Locality and Naming
The type section is located on the southern bank of the Raggyorcaka about 10 km to the north of the Shuanghu Office of Tibet. It was named by Wen Shixuan in 1979.
Lithology and Thickness
Clastics. It is divisible into two parts. Lower part is composed of dark-grey sandy siltstone and limestone, yielding Fusulinida and brachiopods fossils, with a thickness of about 140 m. Upper part is composed of grey-black sandstone and siltstone, intercalated with coal seams, yielding plant fossils (phytolites), with a thickness of 90 m. Between the upper and lower parts there is a fault contact, with no distinct relationship between them.
Synonym: Rejaochaka Fm (as used in Triassic entry in Lexicon)
Relationships and Distribution
Lower contact
Unknown contact relationship with the underlying strata. Next older unit in this region is the middle-Permian Kamrbo Gr (its upper formation is the Ninggongqujiulong Fm)
Upper contact
Conformable contact with the overlying Kanglu Fm of the Lower Triassic
Regional extent
Distributed in the area extending from the Headquarters of Shuanghu Office of Tibet to the Raggyorcaka.
GeoJSON
Fossils
The Fusulinida is characterized by the occurrence of the Palaeofusulina fauna, the Brachiopods comprise the Peltichia, Cathaysia, Squamularia, Spinomarginifera, Leptodus, etc., which are all the zonal fossils or important members of the Changhsing Fm in South China; the Plant fossils (phytolites) are including Selaginellites, Sphenophyllum, Annularia, Lobatannularia, Alethopteris, Compsopteris, etc., which are found to occur often in the Cathaysian flora of the Lopingian Epoch in South China.
Age
Depositional setting
Additional Information