Serongsi Fm
Type Locality and Naming
The type section is located at Serong in Jiangda country, Tibet. It was named by the third area survey team of Sichuan Geological Bureau in 1974. The auxiliary section is located in Pushui Bridge of eastern Jiangda Country. In 1987, Rao Rongbiao et al. suggested that the Serongsi Fm should be abandoned, because of ammonoids Hauerites sp., Cryptenerites sp., Styrites sp. of the Late Triassic Carnian discovered in the limestone at type section, and suggested that the Serongsi Fm dominated by limestones should be classified as the upper part of the underlying Pushuiqiao Fm dominated by clastic rocks.
Synonym:
Lithology and Thickness
The Serongsi Fm, 303 m thick, is mainly composed of gray slate, thick-bedded marble, crystalline limestone, intercalated with purple marble and light-yellow marl, with 5 m of light gray conglomerate at the bottom.
Relationships and Distribution
Lower contact
The Serongsi Fm is unconformable in contact to the underlying Variscan granite or conformable in contact to the underlying Pushuiqiao Fm around the Yaannong of Pushui Bridge in Jiangda Country.
Upper contact
It is disconformable in contact to the overlying Walasi Fm (Fuwalasi Fm).
Regional extent
The formation is restrictively distributed in Serongsi, Walasi, Boluoguse, Handagou and Ailashan.
GeoJSON
Fossils
This formation yields Owenites-Procarnites ammonoid assemblage, conodonts Neospathodus timorensis, N. homeri, N. waageni, N. triangularis, and a few bivalves and gastropods.
Age
Depositional setting
It is interpreted as a marine setting.
Additional Information