Chichengshan Fm
Type Locality and Naming
Eastern Zhejiang The Chichengshan Formation was erected in 1994 when the stratigraphic sorting was made by the Zhejiang Bureau of Geology and Mineral Resources. The section measured for the designation is from Qingxi, the Xitang Village to the west of the Tiantai County of the Zhejiang Province. The Chichengshan Formation represents the member in the upper part of the previous Laijia Fm, which has been attributed to Late Cretaceous. This formation is the third rock formation of the Tiantai Gr.
Lithology and Thickness
The Chichengshan Formation is mainly built up by a suite of purple red moderately thick-bedded massive sandy conglomerate, conglomerate, gravel-bearing sandstone with siltstone, and gray purple red thick-bedded rhyolitic breccia tuff. The Chichengshan Formation is 660.1 m thick.
Relationships and Distribution
Lower contact
Its basal part comprises purple red moderately thick-bedded conglomerate with thin-bedded fine sands and siltstone, which is different from the underlying Liangtoutang Fm consisting of purple red thick-bedded clayey siltstone with conglomerate, and there is a conformable contact between the two.
Upper contact
The overlying strata are obscure. In the east coastal area, the Miocene Shengxian Fm lies unconformably on the Chichengshan Fm.
Regional extent
The formation mainly occurs in the Tiantai, Xianju, Jinyun and Shuhong basins of southeast Zhejiang. Lithologically it is quite persistent and laterally varies considerably in thickness, up to 660.1 m at maximum and 557.1 m thick at Tianyangjin of Tiantai, and over 300 m thick around Yangfu of Xianju.
GeoJSON
Fossils
None listed
Age
Depositional setting
It is of fluvial facies deposited under the hot and arid climate condition.
Additional Information