Nuoco Fm
Type Locality and Naming
The type section lies at Dongbei Hill on the north end of Nuo Co (a glacial lake) west of Lagu Village, Baxoi County, Tibet. It was named by Yin Jixiang in 1984.
Lithology and Thickness
Claystone, Sandstone and Clayey Limestone. Clastic rock (lower part) and carbonate rock (upper part) formations. The Lower Member is composed of gray silty slate, intercalated with fine-grained sandstone and slate interbedded with gray slate and fine-grained sandstone, 250 m thick. The Upper Member consists of gray medium to thick-bedded clayey limestone, purple porphyritic clayey limestone or nodular limestone, with small pyrite crystals and suture structures, 31 m thick.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Upper Devonian Songzong Group (Dev column 25)
Upper contact
Conformable contact with the overlying Lagu Fm
Regional extent
Distributed along Risongzong and Charidong of Bowo, and Yaze to Lagu of Baxoi.
GeoJSON
Fossils
Lower Member yields Brachiopods Fusella cf. tornacensis, Marginatia sp. and Tylothyris pseudoposterrus; Bryozoan Fenestella cf. donaica; trilobites Cyrtosymbole sp., Ditomopyge sp. and Neoproetus sp.; Bivalves Phestia sp. and Dunbarella sp., crinoid stem Pentagonocyclicus sp., etc. Upper Member contains Ammonoid Beyrichoceratoides sp.,
Age
Depositional setting
It is interpreted as a
Additional Information