Awatag Fm
Type Locality and Naming
The type section (not named) lies about 5 km south of 2653 elevation point in the north of Wushi County, the Xinjiang Uygur Autonomous Region (79°11’35”E, 40°58’57”N), remeasured by the No. 9 brigade of No. 13 Team of the Ministry of Geology of China in 1958.
Synonym: （阿瓦塔格组）; The lower and middle parts of Awatag Formation had been split up into two formations, the Wusongger Fm (below) and the Shayilik Fm (above) by biological content. Both formations are actually in the form of lithostratigraphic units but without lithostratigraphic meaning. By lithology, Cai (1999) merged the Shayilik Fm with restricted (upper) Awatag Formation as the lower part of the Awatag Formation and merged the Wusongger Fm with the underlying Xiaoerbulak Fm, forming the upper part of that formation. The Awatag Formation here include only the restricted Awatag and abandoned Shayilik Fm.
Lithology and Thickness
The Awatag Formation is a thick dolomite sequence, interbedded with limestone and edgewise conglomerate. Lower part of the Formation consists of purplish red, grey dolomite with gypsum and halite pseudocrystal, grey, dark grey thick-bedded cherty or chert-nodule-bearing limestone, pinkish yellow, purplish red argillaceous limestone intercalated with edgewise conglomerate. Upper part consists of purplish red mudstone of gypsification, dolomite, pelitic siltstone and argillaceous limestone intercalated with dolomitic limestone and cherty limestone.
Relationships and Distribution
Lower contact
The Awatag Fm rests conformably on the Xiaoerbulak Fm
Upper contact
It is conformably overlain by the Qiulitag Fm
Regional extent
The Awatag Formation is exposed in Bachu-Kalpin Area of Tarim Region, distributed in northwestern of Tarim Platform with outcrops in Aksu, Kalpin, Qipan, Subexi Wushi, Yudaigilik, and Zanbile cities and counties etc. with thickness varying from 77 m to 1060 m
GeoJSON
Fossils
The basal part of the formation yields trilobites Kummingaspis divergens, Chittidilla nanjiangensis, Paragraulos kunmingensis, and Bathynotus holopyge and hyoliths.
Age
Depositional setting
The formation represents mainly deposits of lagoonal facies.
Additional Information