Lamenzi Fm
Type Locality and Naming
Liuhe Basin. It was named by the Regional Survey Party of Jilin Province in 1976. The naming section is located in the area of Lamenzi, Liuhe County, Jilin Province, with its reference section being situated in the vicinity of Wangou Gully, Baishan City.
Synonym: （砬门子组）
Lithology and Thickness
Lower part is composed of grey-white, yellow-brown conglomerates and sandstones, intercalated with yellow-green siltstones. Upper part is grey-green spotted andesites. Thickness of about 1173 m.
Relationships and Distribution
Lower contact
Its base is in a disconformable contact with the underlying middle Jurassic Houjiatun Fm
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Dashatan Fm
Regional extent
The formation is distributed extensively in the areas of Manjiang, Changbai and Funing Counties, Hunjiang City, Tonghua City, and Liuhe and Sanyuanpu Counties of Meihekou City, southern Jilin. In the Liuhe Basin the formation contains less volcanic rocks and their clastics, yet southeasterly the volcanic materials are becoming predominant with fewer intercalated beds of sedimentary rocks. Its thickness varies in a range from hundreds of meters to 1500 m.
GeoJSON
Fossils
At Lamenzi it yields Ostracods as represented by Cypridea? sp., Darwinula? sp., and Gastropods: Probaicalia sp., with skeletal fragments of Reptilia being found occasionally there. At the Shiliudau Gully of Changbai County by the highway to the Baoquanshan Electric Power Station there occur bivalves: Ferganoconcha sp. and Sphaerium sp., and plant fossils such as Equisetum sp., Coniopteris burejensis, Acanthopteris gothani, Onychiopsis sp., Baiera furcata, B. cf. concinna, Pityophyllum sp. and Cunninghamia submanchuria.
Age
Depositional setting
The formation belongs to fluvial-lacustrine deposits, intercalated with deposits of volcanic-eruption facies.
Additional Information
Details on Liuhe Basin stratigraphy (a very small volcanic-lacustrine basin, SE of Songliao Basin, latest Jurassic through early Cretaceous) is within the article at: https://cup.edu.cn/petroleumscience/docs/2022-11/70529bb4f78e4cb4bc6bbf8405b891d1.pdf