Tuxbulak Fm
Type Locality and Naming
The name was proposed by E. Norin in 1928~1932. The type section is located in Tushibulak area, approximately 50 km north of Lop Nur Lake, the Xinjiang Uygur Zizhiqu; the reference section is at 8km east of Altemeishibulak, Ruoqiang (Qarkilik) County, north of Lop Nur. It was first published by the Compiling Group of the Regional Stratigraphical Scale, the Xinjiang Uygur Zizhiqu in 1981.
Synonym: (土什布拉克组)
Lithology and Thickness
The formation consists of gray green, yellow green medium-to coarse-grained arkosic sandstone, micritic sandstone and yellow green pelitic siltstone. Lower part comprises calcareous sandstone with limestone partings. Upper part yields brachiopod Spiroraphe cf. bohemica, Pleurorima sp., Holopea sp., Coelzone sp.
Relationships and Distribution
Lower contact
The formation, 2217 m in thickness, rests pseudo-conformably on the Querquek Fm of the Middle Ordovician (or conformably on the Wuligeztag Fm of the Upper Ordovician).
Upper contact
It is pseudo-conformably overlain by the Shugouzi Fm of the Middle Devonian. In the area Korla, the Tuxbulak Fm is disconformably overlain by the Kelasu Gr of the Lower-Middle Jurassic.
Regional extent
The Tuxbulak Fm is mainly exposed in the areas of Kuluk Tag Mts., Ruoqiang County and Korla City in eastern and northeastern parts of Tarim Basin. In the area south of Muhelayibulak the formation yields brachiopod Lophospira sp., Eotomaria sp., Cyclonema sp., Rophictoma sp., cephalopod Michelinoceras sp.; in the area north of Qiorqiok Mt. the formation bears graptolite Monograptus priodon. On the northern bank of Konqi River the upper part of the formation consists of variegated clastic rock intercalated with limestone layers and there is also conglomerate at the top. Ranges from 869-2417 m in thickness in general.
GeoJSON
Fossils
The upper part of the formation bears gastropod Horotogtum sp., chitinozoa Cingulochitina wronai, etc.
Age
Depositional setting
The Tuxbulak Fm belongs to neritic coarse-fragmental sediments of platform type.
Additional Information