Ketuer Fm
Type Locality and Naming
Dong Yanru named it in 1990. The named profile is located in Yuecan 1 Well, 83°4' E, 40°51' N, in the northeast of Tarim Basin. The reference section is located in Shakan 1 well about 50 km to the southwest of the well. In 1984, Huang Youyuan named a set of thin layers of gray and dark gray mudstone interbedded with yellow siltstone in Yuecan 1 Well as the Manjiaer Group, which can be divided into three groups: lower, middle and upper part, and the age is early, middle and late Triassic. In 1990, Dong Yanru continued to use the Manjiaer Group, and named the lower group as the Ketuer Fm, the middle group as the Akekule Fm, and the upper group as the Halahatang Fm. Lowermost formation in Manjiar Gr.
Synonym: Ketur Fm
Lithology and Thickness
The lithology is gray green, dark gray mudstone, gray siltstone, sandstone. Lower part is dark gray mudstone, silty mudstone with light green gray siltstone, and the bottom part is light gray fine-grained sandstone and fine conglomerate with thickness in 127.5 m. Upper member is composed of greenish-gray mudstone, siltstone, medium-fine sandstone interbedded with dark purple mudstone with a thickness of 179.5 m.
Relationships and Distribution
Lower contact
The conglomerate at the bottom is in unconformable contact with the underlying Paleozoic
Upper contact
The top is conformable contact with the overlying Middle Triassic Akekule Fm
Regional extent
The formation is widespread in the Tarim Basin, and is found in many boreholes from Yuecan 1 well to Shacan 1 well in the south to Minfeng-Qiumo in the north, and the thickness varies from 70 to 500 m.
GeoJSON
Fossils
The lower part contains Charophyte Auerbachichara spp., Prochara spp., Altochara spp.; Microspores: Limatulasporites-Lundbladispora-Taeniaesporites assemblage in the lower part, Cycadopites-Tubermonocalpites -Lundbladispora assemblage in the upper part; Megaspores: Trileites (Calamospora)-Maexisporites- Pusulosporites inflatus assemblage in the lower part, Trileites (Calamospora)-Pusulosporites inflatus- Tuberculatisporites assemblage in the upper part.
Age
Depositional setting
The formation is shallow lacustrine facies
Additional Information