Xiaqiongco Fm
Type Locality and Naming
It was named by Wang Naiwen in 1983. The naming section is located at Guiya (Hama Mts) of Bango county, Tibet (E 89°36′, N 31°45′), with its reference section being located at Boboyara of Bango County, Tibet (Gushan Mts, E 89°50′, N 31°45′).
Synonym: （夏穷错组）; Xiaqiongcuo Fm. According to All China Commission of Stratigraphy (2017), Bureau of Geology and Mineral Resources of Tibet Autonomous Region (1997) considered the Xiaqiongco Fm as a synonym of the Duoni Fm of which geological age was Cretaceous.
Lithology and Thickness
It represents a rhythmic unit composed of grey, grey-green and brown-yellow calcareous shale, quartz-sandstone, quartzite and sandy conglomerate, with a thickness of over 300 m.
Relationships and Distribution
Lower contact
No base having been found in reference area; but regionally, the schematic strat column indicates the next older unit as Jienu Gr
Upper contact
No top has been found at type section. Regionally, it is overlain conformably by the Guiya Fm.
Regional extent
The formation is distributed largely in the Guiya, Boboyara and Xiaqiongco areas of Bango County, and with a consistent lithology. In most cases of the above-mentioned areas no base of the formation has been found.
GeoJSON
Fossils
In the Guiya and Boboyara areas the formation yields bivalve fossils as represented by Amputina florae; ammonites fossils as represented by Neocosmoceras sp., Neocomites neocomiense, Kilianella cf. leptosoma, K. cf. pexiptycha, Thurmanniceras cf. salientinum, Olicostephanus sp., Phylloceras serum, Berriasella sp., Spiticeras sp. and Calliptychoceras sp., as well as coral and Gastropod fossils.
Age
Depositional setting
Additional Information