Lagongtang Fm
Type Locality and Naming
It was named by Li Pu and others as the “Lagongtang System” in 1955. The naming section is located at Lagongtang of Luolong County, Tibet, with its reference section being situated at Mali of Luolong County, Tibet (Xu Yulin and others, 1990).
Synonym: （拉贡塘组）, Gongtang Fm
Lithology and Thickness
The formation represents grey shale with ferruginous concretions, intercalated with sandstones, with an increase in the amount of sandstones upwards gradually. It is 300-500 m in thickness.
Relationships and Distribution
Lower contact
It is in a conformable contact with both the underlying middle Jurassic Liuwan Fm
Upper contact
It is in a conformable contact with the overlying lower Cretaceous Duoni Fm
Regional extent
The formation is distributed extensively in the Baxiu-Lajiu and Luolong-Dingqing areas along the Nujiang (Nu River) valley, with a consistent lithology, and with a thickness of 34-2090 m.
GeoJSON
Fossils
In the areas of Lagongtang and Dingqing it yields abundant late Jurassic ammonites as represented by Aulacosphinctes sp., A. aff. ophidioides, Metapelteceras aff. diversiforme, Virgatosphinctes denseplicatus, V. aff. subquadratus, V. aff. kontkiewiczi, Aspidoceras cf. babeanum, Kosmatia tenuristriata, Hoplocardioceras decipiens and Holcophylloceras cf. polycum; and bivalves such as Endolium proeteus. In the area of Mali it yields such ammonites as Kinkeliniceras catillus, Petoceratoides semirugosum, Macrocephalites (Pleurocephalites) sp., Reineckeia sp., Prososphinctoides cf. manialensis, Alligaticeras cf. alligatus, Pterolytoceras cf. exticum.
Age
Depositional setting
Additional Information