Qiablin Fm
Type Locality and Naming
South Lhasa Block - Xigaze forearc Basin. The Qiablin Formation was erected by Wu Haoruo, Wang Dongan and Wang Liancheng. The section for the designation is at Qiablin of the southern bank of the Yarlung Zangbo River. The reference section is in Dazuka-Nisila on the southern bank of the Yarlung Zangbo River of the Xigaze County, Xizang.
Lithology and Thickness
The Qiablin Formation is represented by green gray and locally purple red siltstone with sandstone and conglomerate lenses (0.3-0.2 m), with the gravels being composed primarily of jasperite, chert and various volcanic rocks. The Qiablin Formation is 60 m thick.
Relationships and Distribution
Lower contact
Unknown. At the type section, the base it thrust onto the younger Dazuka Fm (E3-N1) by a fault.
Upper contact
Conformably overlain by the Sangzugang Fm.
Regional extent
The present formation occurs in Dazhuka, Qiablin west of and Xishan of Xigaze. It varies considerably in lithology. In Xishan of Xigaze it is represented by gray black sandy shale with carbonaceous siltstone and grit, with a thickness of 140 m; in Dazhuka gray green and purple red shale, sandy shale, siltstone and conglomerate with a thickness of 60 m; and to the west of Xigaze purple red shale and sandy shale with a thickness of 37.5 m.
GeoJSON
Fossils
In the above areas, the lower part of the formation is missing and contacts with the underlying strata mostly by fault, the top is overlain disconformably by the Orbitolina limestone of the Sangzugang Formation. It contains radiolaria Thanarla pacifica, T. brouwei, Acaeniotyle umbilicata, Hiscocapsa asseni, Pseudodictyomitra cf. lilyae, Crucella remanei, Podobursa cf. typica, Pantanellium cf. Berriasianum, Staurosphaeretta sp., Xitus cf. spiculariu, Dictyomitra sp., Protoxiphotractus sp., Archaeodictyomitra sp., Holocryptocapsa sp., which refer an Aptian age to the formation.
Age
Depositional setting
Additional Information