Duorang Gr
Type Locality and Naming
Named by Liang Dingyi and others in 1991. The named section is located in Duorang, Burang County, Tibet.
Synonym:
Lithology and Thickness
It is mainly composed of interbedded black shale and black thin argillaceous limestone. The thickness is greater than 400 m.
Relationships and Distribution
Lower contact
The bottom is marked by black shale in conformable contact with the underlying Zharinaya Fm. In Zhada region, it is underlain by the Mangxiangyu Fm
Upper contact
The top is marked by black shale. Next higher unit is the Gongzula Fm of Norian.
Regional extent
This group is only distributed in Dingga Pass and Duorang, which border Tibet's Burang and Nepal.
GeoJSON
Fossils
Bivalves include Daonella simplicosta, Halobia Fallax, Pteria mediocalcis, Monotis salinaria, M. anjuensis, Entomonotis sp. from bottom to top; ammonoids are concentrated in the middle and upper parts, including Sirenites cf. vredenburgi, S. tinkarensis, Hannaoceras sp., Cyrtopleurites ngariensis, Episculites ngariensis, E. burangensis, Dimorphites weberi, Placites oldhami, Anotomites herbichi, Pinacocestes cf. rex, Proarcetes gaytani, etc.; see conodont Epigondolella postera, Neogondolella navicula steinbergensis and a few brachiopods on the upper part.
Age
Depositional setting
Represents a semi-deep marine environment.
Additional Information