Bianqiao Fm
Type Locality and Naming
The naming section is located at a gypsum mine and Wangjiazhuang in the central part of the Pingyi basin, Shandong. Proposed first by Xu Baozheng and Wang Shilin (1983) and later formally used by Chi Hongji et al. (1986) in the book Definition of the Paleogene in the Pingyi Basin, Shandong.
Lithology and Thickness
It consists of purplish red sandy mudstone, sandstone and variegated conglomerate with light gray or dark gray marlstone, black carbonaceous mudstone and gypsum. The thickness is up to 600–750 m.
Relationships and Distribution
Lower contact
It has an unconformably contact with the underlying Early Cretaceous Qingshan Fm. However – see "Age" below – it was originally upper part of late Cretaceous Wangshi Fm.
Upper contact
Disconformable or unconformable contact with the overlying Early to middle Eocene Guanzhuang Fm.
Regional extent
The formation is of relatively restricted distribution, only in the Bianqiao area, Pingyi. It is exposed poorly at the surface and relatively completely in the wells.
GeoJSON
Fossils
It contains abundant but monotonous species of Cypridea as well as Metacypris, Candona etc.; charophytes are represented by Stephanochara and Peckichara; gastropods are Physa yuanchuensis, Valvata menyinensis etc.; the sporopollen assemblage is dominated by pollen of angiosperms, of which the pollen of the Ulmaceae has a high content and the spore content of pteridophytes is higher than the pollen of gymnosperms.
Age
Depositional setting
Primarily a sequence of lacustrine deposits.
Additional Information