Elantag Fm
Type Locality and Naming
The type section is in Huanxing Hill on the south slope of central Altun Mountain (90°58′58″E, 38°56′30″N), Xinjiang. Zhang (1970) reported the trilobites from the Elantag Fm. Zhong et al. (1994) remeasured and redescribed in detail the type section and adjacent Yaolesayi section, and divided it into two lithological parts.
Synonym: (额兰塔格组）
Lithology and Thickness
Lower part of the Formation is composed of medium- to thin-bedded nodular bioclastic micritic limestone, marl and sandy mudstone. Upper part is medium- to thick-bedded bioclastic micritic limestone, laminated argillaceous micritic limestone. In the type area, the Elantag Fm is 347 m thick.
Relationships and Distribution
Lower contact
It rests unconformably on the Qingbaikou System (early Neoproterozoic). Regionally, the next older unit is the Torsuqtagh Fm of late Cambrian.
Upper contact
It is conformably overlain by the thin-bedded limestone intercalated with sandstone in the lower part of the Huanxingshan Fm
Regional extent
GeoJSON
Fossils
This stratigraphic unit yields conodonts of Paraserratognathus cf. paltodiformis assemblage, Aurilobodus leptosomatus-Plectodina assemblage, Aurilobodus leptosomatus-Lexodus disectus assemblage and Tangshanodus tangshanensis assemblage, in ascending order; Nautiloid Wutinoceras-Adomsoceras assemblage in the lower part and Dideroceras-Ormoceras-Armenoceras assemblage (a part) in the upper; Stromatopora Labechia-Turachia assemblage in the lower part and Pseudolabechia-Rosenella assemblage in the upper; brachiopods of Orthis-Tritoechia assemblage in the lower part, Sinorthis-Altunella assemblage in the middle and a part of Taphrorthis-Leptellina-Altunella assemblage in the upper; trilobites of Basilicus (Basiliella)-Megalaspides assemblage; gastropods of Pararaphistoma cf. qualteriatum-Maclurites zhazishanensis assemblage.
Age
Depositional setting
Additional Information