Kunjirap Fm
Type Locality and Naming
Karakorum. The type section is located on the upper reaches of Tash Kurghan River, Xinjiang, with its reference section being situated at Gannan Kule of Salijile northwest of Bayidaban [mountain pass, 34.6N, 79.9E, 5.3 km = between TJ28 and TJ36), Xinjiang. It was named by the Compiler
Jingeng Sha (coordinator) Group for the Regional Stratigraphic Chart of Xinjiang Uygur Autonomous Region in 1981.
Synonym: （红其拉甫组）
Lithology and Thickness
It represents light-grey to dark-grey, light-rose, thin- and medium-bedded and massive limestones, oolitic limestone, bioclastic limestone and brecciated limestone, and gradating facially into grey-green sandstone, siltstone, gritstone in some regions, intercalated locally with gypsum layers. It is with a thickness of 2577 m.
Relationships and Distribution
Lower contact
It is in a conformable contact with the underlying Longshan Fm
Upper contact
No top of the formation has been found. Regionally (Karakorum), next younger unit is the Chongtashi Fm clayey sandstone of lower Cretaceous.
Regional extent
Karakorum. The formation is distributed extensively, and is consistent in lithology, and only in the area of Karachigu it turns to be predominated by limestone, intercalated with siltstone and quartz-sandstone, with a thickness of 120-2570 m.
GeoJSON
Fossils
It yields abundant ammonites, bivalves, Brachiopoda and coral fossils. In the area of Kunjirap the formation yields such ammonites as Virgatosphinctes sp. and Kellawaysites? sp.; bivalves as represented by Camptonectes (C.) sp., C. (C.) rugosus, Gerillella sp., Astarte sp., Liostrea birmanica, and Chlamya (Radulopecten) ovagams. In the area of Karachigu the formation yields ammonites: Virgatosphinctes multifasiatus, V. frequens, V. denseplicatus, Phylloceras sp., Perisphinctes curvicostata and P. furcula, as well as bivalves.
Age
Depositional setting
Additional Information
Age:
For graphic purposes, assigned as spanning the Late Jurassic (conformable on Middle Jurassic Longshan Fm; and containing Virgatosphinctes sp. ammonites of Tithonian).
Age span:
Beginning stage: Oxfordian
Fraction up in beginning stage: 0.0
Beginning date (Ma):
Ending stage: Tithonian
Fraction up in ending stage: 1.0
Ending date (Ma):
Depositional setting:
Depositional-pattern:
Additional Information
Compiler
Jingeng Sha (coordinator)