Chengqiangyan Gr
Type Locality and Naming
Sichuan Basin – central and northwest. Zhao Yazeng and Huang Jiqing established the Chengqiangyan bed in 1931. The section measured for the designation is in the Jianmenguan area of Guangyuan County, Sichuan Province. The Chengqiangyan bed stands for the red clastic rocks over the Guangyuan bed in the Jianmenguan area of Guangyuan, and was assigned to Paleogene. In 1965 the Second Regional Geological Survey Team of Sichuan renamed it the Chengqiangyan Group and assigned it to Cretaceous. In 1982 Wang Mengyun et al assigned it to Early Cretaceous.
Lithology and Thickness
In the central Sichuan Basin, present group is divided in ascending order into the Penglaizhen Fm (when included in this Group), Cangxi Fm, Bailong Fm and Qiqusi Fm. On the north and northwest margin of the Sichuan basin, it is divided into the Lianhuakou Fm (when included in this Group), Jianmenguan Fm, Hanyangpu Fm and Jiange Fm.
Relationships and Distribution
Lower contact
In central Sichuan Basin, the lower boundary is marked by the “Gaojiashan Conglomerate” and contacts conformably with the underlying Penglaizhen Fm comprising green red mudstone interbedded with gray purple fine sandstone and siltstone. If the Penglaizhen Fm is included in this Group, then the underlying formation is the Suining Formation of early Tithonian.
In north to northwest Sichuan Basin, its conformable base is marked by the occurrence of massive conglomerate is distinguished from brick-red sandy mudstone of the Lianhuakou Fm. If the Lianhuakou Fm is included in this Group, then the underlying formation is the Suining Formation of early Tithonian.
Upper contact
In central Sichuan, the Gudian Fm is the next younger unit. In south Sichuan Basin, a major erosion or non-deposition through the rest of the Cretaceous. But, for regional generalized column (including south Sichuan Basin), the next younger (or overlapping) unit is the Jiading Gr (Wotoushan Fm).
Regional extent
North through central Sichuan Basin (albeit with different formation nomenclature)
GeoJSON
Fossils
None listed
Age
Depositional setting
Additional Information