Ershi'erzhan Fm
Type Locality and Naming
It was named by No. 1 Team of the No. 2 Regional Survey Party under the Geological Bureau of Heilongjiang Province in 1985, and was first cited publicly by Wang Ying in 1985. The naming section is located on the Rear Hills of the No. 22 Highway Station of the Nenjiang−Mohe Highway, Tahe County, Heilongjiang Province. Lower (third) formation in Emurhe Gr.
Synonym: （二十二站组）
Lithology and Thickness
It is composed of grey and grey-green feldspar-lithic sandstone, siltstone and fine-grained sandstone, and 888.4 m in thickness.
Relationships and Distribution
Lower contact
It is in a conformable contact with both the underlying Qilinji Fm
Upper contact
It is in a conformable contact with the overlying Mohe Fm
Regional extent
It is distributed largely in the eastern part of the upper Heilongjiang Depression, with its exposures being found at Ershi’er Station, Malin, Walagan, Yaozhan Station and Guihua Station, stretching in the form of an east-west belt, and from west to east the grain size of the sediments is getting coarser, and the thickness of the sediments is getting greater gradually.
GeoJSON
Fossils
It yields bivalve fossils as represented by Margaritifera isfarensis, Margaritifera (Margaritanopsis) walagenensis, Ferganoconcha sibirica, F. subcentralis, Sibireconcha cf. anodontoides, Pseudocardinia? jenisaica, Cuneopsis cf. johannisboehmi, Unio sp.; Gastropoda: Gyraulu sp., Valvata cf. turgensis, Ampulovalvata suturalis amurensis; conchostraca Euestheria sp. and Triglypta? sp., as well as plant fossils: Coniopteris hymenophylloides.
Age
Depositional setting
The formation represents fluvial and shallow-lake deposits, and is characterized by a good development of large-, and middle-scale oblique and cross beddings.
Additional Information