Pusela Fm
Type Locality and Naming
It was named by Liang Dingyi and others in 1991. The naming section is located at the Pusela Mts east of the Mayang-Jiesheng region, Zada County, Tibet (E 79°00′, N 31°50′), with its reference section being situated in the Caili area 10 km southwest of the Kejia region, Pulan County, Tibet (E 81°20′, N 30°10′).
Synonym: （普色拉组）
Lithology and Thickness
Its basal part is composed of grey-white medium-bedded dolomitized microcrystalline limestones intercalated with black argillaceous limestones. Lower part consists of green-grey medium-, and thin-bedded microcrystalline limestones intercalated with wormy limestones and brecciated limestones. Upper part consists of grey-black medium-, and thin-bedded bio-microcrystalline limestones intercalated with oolitic limestones, sandy limestones associated with algal limestones, with a thickness of over 375 m.
Relationships and Distribution
Lower contact
The basal part of the formation is in a conformable contact with the underlying upper Triassic black-grey thick-bedded dolomitic limestones.
Upper contact
In the Caili area of Pulan County the top part of the formation with a layer of grey-white medium-bedded quartz-sandstones is in a continuous transitional contact with the light-grey thick-bedded limestone at the base of the overlying middle Jurassic Series or Youxiugou Fm
Regional extent
The formation is distributed mainly in the areas of Pusela and Luba-Nuba of the Mayang region, Zada County and of Caili, Pulan County, with a consistent lithology, and with a thickness of 25.7-440 m. It is in a conformable contact with both the overlying middle Jurassic Series and the underlying upper Triassic Series.
GeoJSON
Fossils
In the Mayang region it yields such bivalves as Weyla ambongoensis, Entolium calvus, E. cf. erecta, Liostrea sublamellosa, L. irregularis, Pseudavcella marstoma and Plagiostoma cf. punctata, while in the Caili area of Pulan County it yields Chlamys cf. matapwaeensis.
Age
Depositional setting
Additional Information