Dongdacun Fm
Type Locality and Naming
Named in 1985 by Zou Chengjing and Han Zizhang. The named section is located from Zuogong County to Dongda Village in Tibet.
Synonym:
Lithology and Thickness
It is dominated by massive limestone and bioclastic limestone, with clastic rocks appearing in the upper and lower parts. Lower part is composed of white quartz conglomerate, shale and limestone with multiple layers of siderite; Middle part is gray thick-layered massive limestone and bioclastic limestone; Upper part is mainly gray-black thick layered mudstone with thin-layered silt sandstone, fine sandstone and multilayer bioclastic limestone. The total thickness is 882 m.
Relationships and Distribution
Lower contact
It was in unconformity contact with the underlying Paleozoic.
Upper contact
It was in false conformity contact with the overlying Zuogong Fm
Regional extent
GeoJSON
Fossils
It is rich in fossils of bivalves, brachiopods, corals and bryozoans. Bivalve fossils have Schafhaeutlia cf. manzarinii, Neomegalodon sp., Cornucardia sp. Coral includes Margarosmilia confluens, Thecosmilia clathrata, Procyclolites elegans, Margarophyllia cf. crenata, Conophyllia sp., Volzela chagyabensis, Distichophyllia sp. etc. in ascending order.
Age
Depositional setting
This group is a coastal-shallow marine setting, distributed in Zuogong County, Tibet, east of the Nujiang fault and west of the Lancangjiang fault.
Additional Information