Jiangligou Gr
Type Locality and Naming
The type section is located at Guomugou-Jiangligou, Tongren County, Qinghai Province. It was named by The Seventh Geological Team of Qinghai Geological Bureau and Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences in 1976, and firstly cited by Bureau of Geology and Mineral Resources of Qinghai Province in 1991.
Synonym: Rao Rongbiao et al. (1987) called this formation as Longwuhe Group's Shangyan Fm. See the “Guomugou Formation” for details.
Lithology and Thickness
It mainly consists of gray, dark gray fine-grained feldspar quartz sandstone, quartz feldspar sandstone intercalated with argillaceous slate, calcareous slate, thin limestone, siliceous banded limestone, partially intercalated with fine-grained rock and coarse sandstone. The thickness is 687 m.
Relationships and Distribution
Lower contact
The bottom boundary is marked by the appearance of gravelly limestone and the underlying Guomugou Fm
Upper contact
The top boundary by the disappearance of black slate. It is conformable contact with the overlying Gulangdi Fm
Regional extent
This formation is mainly distributed in Xinghai, Zeku, Tongren and Jianzha areas in Qinghai Province. The area from Jianzha Longwu River Mouth to Shinao River is dominated by siltstone and slate intercalated with limestone. Outside of the named section, the group is within the distribution range, with a thickness of 696-4790 m.
GeoJSON
Fossils
Ammonoids: Xenoceltites sp., Columbites sp., Amauroceltites sp., Meekoceras sp.; Bivalves: Leptochondria sp., L. cf. bittneri, Schafhaeutlia sp., Mytilus eduliformis praecursor.
Age
Depositional setting
Various pictographic impressions are often seen in the upper part of this formation, showing the characteristics of isocratic rocks after the turbidite layer has been transformed by the submarine ocean currents of the contour flow.
Additional Information