Zhangqiao Fm
Type Locality and Naming
Heifei Basin, north zone. The Zhangqiao Formation was erected by the First Prospecting Brigade under the Ministry of Geology in 1964. The section for the designation is down the comprehensive borehole about 22 km south of the Dingyuan County of Anhui.
Lithology and Thickness
The Zhangqiao Formation is represented by a set of brick red and brown red gravel-bearing medium- to fine-grained sandstone, siltstone, clayey siltstone and mudstone. The Zhangqiao Formation is in excess of 987 m in thickness.
Relationships and Distribution
Lower contact
Its base marked by the occurrence of sandy conglomerate is distinguished from and lies disconformably on the underlying Qiuzhuang Fm (=Xiangdaopu Fm).
Upper contact
Its is unconformably under the overlying Paleogene strata.
Regional extent
The formation mainly occurs in the Dingyuan County, Feidong County, Jiashan, Fengyang, etc. It becomes coarser in lithology and increases in the amount of conglomerate and sandy conglomerate. In the Beihuaiyang area, the strata that are equivalent to the formation are called the Sanjianpu Fm.
GeoJSON
Fossils
Down the well No.She-01 in the Feidong basin, it yields Ostracods Talicypridea amoena, Cypridea cavernosa, Cyclocypris aff. calculaformis; Sporopollen grains Cycadopites spp., Classopollis spp., Schzaeoisporites spp. with a high abundance; Angiosperms of Aquilapollenites sp., Callistopollenites radiatostriatus, Ulmipollenites sp.
Age
Depositional setting
It belongs to lacustrine deposition within the basin and to lake shore-piedmont deposition on the margin of the basin.
Additional Information