Baliqliq Fm
(22), mid-Early Permian
Type Locality and Naming
The type section is located in the vicinity of the Subash area to the west of the Keping County, Xinjiang. It was named by Groeber P. in 1914.
Lithology and Thickness
Marl, limestone and volcanics. The formation is composed of black and grey thin- to medium-bedded marls and thick-bedded microcrystalline bioclastic limestones and bioclastic micritic limestones that yield abundant polyphyletic fossils. The formation is characterized by the predominance of marls and limestones, with the increase in the amount of the clastic rocks in the direction towards the Kepingtag. Lower part of the formation consists of volcanic rocks, intercalated with limestone lenses. Upper part of the formation being composed of limestone, and thinning towards both the eastern and western sides of the region until pinching out. The thickness is about 170 m.
Relationships and Distribution
Lower contact
It is in a conformable contact with the clastic rocks of the underlying Wutankule Fm.
Upper contact
It is in a conformable contact with the overlying Kalundar Fm.
Regional extent
The Baliqliq Fm is distributed mainly in the areas of Piqiang Mt. and Subash area of Keping County, as well as in the area to the east of the latter.
[Note: The lower Volcanic unit is part of the Tarim Large Igneous Province (LIP) of Early Permian, which correlated to the volcanics in the lower Kupukuziman Fm and the Kaipaizileike Fm at nearby (NE of Kalpin) exposures at Yinganshan.]
GeoJSON
Fossils
Fusulinida fauna: predominance of Schwagerina and Nankinella known as the Schwagerina chihsiaensis-Nankinella hunanensis assemblage (Xiao Shilu et al., 1987), followed by the establishment in ascending order of the Nankinella-Sphaerulina and the Parafusulina splendens zones (Zhang Siben, Gu Guowei (1991) having taken part in it);
Brachiopod fauna: Liraplecta-Choristites tarimensis assemblage with Araxathyris and Beecheria being the most abundant; Cephalopoda: Artinskia subaskiensis, Czheloceras subushiensis; Bivalves: Aviculopecten kunlunensis-Schizodus jakovlevi assemblage; Bryozoan: Fenestella kepingensis, Penniretepora sp., Streblotrypa grandis, S. sinensis and Ascopora sp.
Age
Depositional setting
It is interpreted as a semi-closed lagoon and a low-energy, fairly deep-water environment. The lower Volcanic unit is part of the early PermianTarim Large Igneous Province (LIP).
Additional Information