Puchenpra Fm
Type Locality and Naming
" The Puchenpra Fm., introduced by Garzanti et al. (1994a), is separated from the Thini Chu Gr since it is underlain by a major unconformity of great regional significance (``break-up unconformity'' of Sciunnach and Garzanti, 1996).
Synonym: Dolpo Fm (in Dolpo region)
Lithology and Thickness
Sandstone; but with a Nar-Tsum Spilites Fm of tholeitic basalt in lower part and ending in a "topmost biocalcarenites" grainstone. " The Puchenpra Fm, redefined as represented by only locally fossiliferous terrigenous sediments, is subdivided into three members (members A, B and C of Garzanti et al., 1994a). … In central Dolpo, the first two members of Sakmarian/Artinskian age are reduced to a single veneer of sediment mantling the basal unconformity, while the third member of Wordian/Capitanian to Wuchiapingian age is particularly well-developed and subdivided into four lithozones ("Costiferina arenites'', "ochre pelites'', "estuarine quartzarenites'' and "black shales and glaucophosphorites'' of Sciunnach and Garzanti, 1996) separated by minor unconformities (i.e. sequence boundaries)." Thickness is 125-150 m in central Dolpo and 100-125 m in Manang.
Relationships and Distribution
Lower contact
Unconformity. Depending upon location, the next older unit is the Atali Quartzite Fm (Dolpo region) or Braga Fm (Thakkhola-Manang region).
Upper contact
Disconformity, then overlain by the Tamba Kurkur Fm (base of Thinigaon Gr)
Regional extent
"The unit shows significant lateral variations from Dolpo to the Manang type-area. … The uppermost lithozone displays some lithological similarities with the Wuchiapingian Gungri Fm of the Spiti-Zanskar Synclinorium, hence it was called "Kuling Fm " in some previous papers (Garzanti et al., 1992; Baud et al., 1996), but such usage should be dropped, because the whole of the Puchenpra Fm. is in fact an equivalent of the Sakmarian/Wuchiapingian Kuling Gr of the Spiti-Zanskar Synclinorium (Garzanti et al., 1996b). … The correlative arenaceous Qubu Fm and marly to bioclastic Qubuerga Fm of S. Tibet (Sun, 1993) reach a much greater thickness (about 500 m) just east of the Nepal/Tibet border (Garzanti and Angiolini, 1999). The about 200 m thick carbonate-pelite alternations locally including patch-reefs observed in the Shiar Valley by Fuchs and Paudel (1998) most likely document the lateral transition between the upper part of the Puchenpra Fm (Member C) and the Qubuerga Fm of Tibet."
GeoJSON
Fossils
Age
Depositional setting
Additional Information
"The Upper Permian succession is characterized by significant lateral variations, and estuarine quartzarenites intercalated within transgressive shelf mudrocks in Dolpo pass laterally to transgressive shelf mudrocks and hybrid arenites in western Manang and finally to fully pelagic conodont-bearing carbonates, which began to be deposited as early as the Roadian/Wordian in eastern Manang (Nicora and Garzanti, 1997)."