Denytangga Fm
Type Locality and Naming
Synonym: 德尼塘嘎组; Denitangga Fm
Lithology and Thickness
The formation, about 700 m in thickness, is dominated by purple, yellowish grey and dark grey thin-to-medium bedded dolomitic marble, argillaceous marble and bioclastic limestone of marine facies (Figure).
[Figure. The lower part of Denytangga Fm at the typical area of Burang Xian, Ngari Diqu, Xizang (Photography by Wang Guangxu)]
Relationships and Distribution
Lower contact
The formation conformably contacts onto the underlying Songmusong Fm of the Upper Ordovician
Upper contact
it may probably be in unconformable contact with the overlying Qiangla Fm of the Lower Devonian or is just cut by fault.
Regional extent
The Denytangga Fm is exposed discontinuously from north of Gangjiu in Zhongba Xian to Denytangga of Burang Xian. Eastwards from the type section locality carbonate rock increased and southwestwards from there clastic rock considerably increased. The thickness of the formation is over 353 m in the Laangcuo area.
GeoJSON
Fossils
It bears corals, Stromatopora, Bryozoa, brachiopod, etc. with the main elements as follows: corals Kodonophyllum sp., Heliolites sp., Guizhoustriatopora sp., Amplexoides sp., Thamnopora zandaensis, Cladopora sp.; stromatopor Actinostroma sp.
Age
Depositional setting
Additional Information
The formation was considered as a junior synonym of Pulu Fm by Xia (1997), the concept of Pulu Fm was defined broadly to include many formations, Pazhuo Fm, Jijiu Fm, Qiangla Group, Denytangga Fm, etc. The authors inclined to keep the names until further works proving the inconsistency of lithology, fossils, facies etc. among the formations.