Ehuobulake Gr
Type Locality and Naming
Huang Jiqing was named in 1943 and officially published in 1947. The named profile is located in the Okhoblak area in the northwest of Kuqa County, Xinjiang; the reference profile is located in the Buulebaoguzigangou of Kuche County.
Synonym: Okhobrac Gr (as used by Tong et al., 2019). Initially, it was named "Okhobrak System", and the age was set as the Triassic; in 1952, the 13th aerial survey team of the former Soviet Union was renamed as the group, and the age was classified as the early Late Triassic; in 1960, Li Minting and Yong Tianshou were renamed as the group; in 1962 Xingjian and Zhou Zhiyan were formally published as a group in the "Mesozoic Terrestrial Stratigraphy in China"; from 1977 to 1981, the Xinjiang Uygur Autonomous Region Regional Stratigraphic Table Compilation Group was still called the group and was classified as the Lower Triassic. This Lexicon uses that assignment.
Lithology and Thickness
It is composed of two sets of gray-green fine clastic rocks and a set of light gray-red and purple-red medium-coarse clastic rocks. The bottom of the First green layer (lower green layer) is purple-grey, gray, and gray-white conglomerate with a layer of red coarse sandstone, Above it is gray-green fine clastic rock, middle sandstone, middle-thin fine sandstone intercalated with silty mudstone. The first Red layer (lower red layer) is thick layered gray-red conglomerate, sandy conglomerate, and coarse-grained. The lithic sandstone has developed oblique bedding. The Second green layer (upper green layer) has gray-white conglomerate at the bottom, and gray-green siltstone intercalated with sandstone and gray-black silty mudstone on the top. The thickness is 407.6 m.
Relationships and Distribution
Lower contact
At Kuche, the bottom is in pseudo-integrated contact with the underlying Upper Permian Biyoulebaoguzi Gr (Buulebaoguzi Gr) with a huge thick layer of conglomerate.
Upper contact
The top is in integrated contact with the overlying Karamay Fm at Kuche. At Tuoyun in South Tianshan, the schematic stratigraphic column indicates an upper disconformity, then overlaid by a Yangye Fm of Middle Jurassic (not yet in Lexicon).
Regional extent
This group is mainly exposed in the area from Kuqa to Baicheng, with a thickness of 100-973 m. It is also widely distributed in the Tarim Basin. The lithology becomes darker and thinner, with a thickness of up to 500 m.
GeoJSON
Fossils
Palaeoliminadia cf. komiana, Pseudestheria cf. toricata, P. cf. nordvikensis, P. nanjistheria, Cyclostherioides cf. dalongkouense, Falsisca multilinearis, Cornia kuqaensis, Diaplexa cf. varispordicta; microspores are divided into lower parts assemblage and upper Cycadopites-Tubermonocolpites-Lundbladispora assemblage; Plants (Kucha River region) Equisetites sp., Cladophlebis sp., Sphenopteris sp., Voltzia heterophylla, Albertia sp.; Chara Auexbachichora xinjiangensis, A. spp., Stomocarsa cupiformis, Porochara spp., Altochara sp.; Trileites- Calamospora (Maexisporites)-Pusulosporites inflatus in the lower part of the megaspore and Trileites- Bacutriletes-Pusulosporites inflatus in the upper part.
Age
Depositional setting
It is a river-shore lake facies deposit.
Additional Information