Quehala Gr
Type Locality and Naming
In 1983, Rao Rongbiao et al. divided the famous "Shading Slate Series" in eastern Tibet into two parts: the Middle, the Lower Triassic Series and the Upper Triassic Series. In 1987, Rao Rongbiao et al. named it the Xihu Gr and the Kehaying Gr (now named as Quehala Gr) respectively. The named section is located in the Kuhala mountain pass with an altitude of 5070 m leading to Yidaliang in Dingqing County, Tibet.
Synonym:
Lithology and Thickness
Flysch. Three sedimentary cycles are mainly composed of gray fine-grained quartz sandstone siltstone interbedded with black slate and limestone. Each cycle is coarser at the bottom and finer at the top, and the limestone contains siliceous bands. The bottom of the lower cycle is conglomerate. The gravel composition is mainly quartz, followed by limestone, with a thickness of 290 m. The thickness of the middle cycle is 1245 m; The upper cycle is characterized by yellowish brown sandstone and calcareous slate gradually increasing and siliceous rocks with a thickness of 1126 m.
Relationships and Distribution
Lower contact
At the bottom, the conglomerate contacts with the Xihu Gr of the underlying and middle Permian
Upper contact
At the top in type area, unconformable contact with the Lagongtang Fm of the overlying middle and upper Jurassic. Regionally, there is a Marri Fm of lower-Middle Jurassic between.
Regional extent
This group is mainly distributed in Tibet Nagqu, Luolong area.
GeoJSON
Fossils
In the middle of the strata, corals: Thamnasteria rectilamellosa. Stylosmilia tibetanus, Isastraea sp., bivalve fossils Elegantinia elegans. Moerakoa burmensis, Nuculana sp. At the top of the strata, corals: Thamnasteria sp., Isastraea propinqua, Isastrocoenia tibetanus, Mylophyllia cf. mojovari; gastropods: Coelocaenia sp.
Age
Depositional setting
It is interpreted as semi-abyssal to abyssal turbidite flysch and siliceous deposit.
Additional Information