Kunkelaqi Fm
(24), Kungurian Stage (late Cisuralian Epoch; late-Early Permian)
Type Locality and Naming
The type section is located at the Karagaiyelega Valley of the Kunkelaqitag to the southwest of the Aheqi County, Xinjiang. It was named by the Geological Research Institute of Xinjiang and the Institute of Geology of the Chinese Academy of Geological Sciences jointly in 1987.
Lithology and Thickness
Limestone. The Lower part represents chiefly reef-core subfacies, and is composed of grey and dark-grey algal-reef limestone. The basal part of the formation is characterized by the occurrence of limestone and being intercalated with calcareous sandstone, volcanic-mud spherical tuff. The Upper part consists of back-reef-subfacies brecciated limestone, algal limestone and siltstone. The reef-building organisms are dominated by blue algae, with the rest of it comprising as well as the Tubiphytes, Gyroporella, etc. The reef-attaching organisms comprise Fusulinida, brachiopods and bryozoan. Thickness ranges from 200 m to 1000 m.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Kak Fm.
Upper contact
Regional extent
Distributed in the Muziduke region, where within the formation there are developed reef-bodies of varying thickness ranging from 200 m to 700 m, thus resulting in a great change in the thickness of the formation, as being of 700-1000 m in the Kunkelaqitag area, and being of only 200-300 m in the Zhongkatag area.
GeoJSON
Fossils
Lower part of the formation yields Fusulinida represented by Pamirina sp., Robustoschwagerina tumida, Eoparafusulina sp., Pseudofusulina crassispira.
Age
Depositional setting
It is interpreted as a basal subtidal low-energy environment, where there are developed the Nankinella and Staffella, with an upwards transition to platform-marginal reef-facies deposits.
Additional Information