Xingshikou Fm
Type Locality and Naming
It was named by Yang Jie as the Xingshikou Subseries in 1957. The naming locality is situated in the area of the Xingshikou Village of the Eight Scenery Spots on West Hills of Beijing City, with it reference section being located on the East Hill Ridge of the Tanzhe Temple, Mentaogou District, Beijing City. Lowermost formation in Mentougou Gr.
Synonym: （杏石口组）
Lithology and Thickness
It represents an alternating layer of black and yellowish-brown shales and silty shales (in some cases there would occur brown-yellow slates instead) in association with grey and grey-black siltstone and sandstone, intercalated sometime with conglomerate and coal seams, being possessed of basal conglomerate (commonly being tens of centimeters to several meters), with a thickness of 31-610 m.
Relationships and Distribution
Lower contact
It is in a disconformable contact with the underlying Shuangquan Fm of Permian-Triassic.
Upper contact
It is in a disconformable contact with the overlying Nandaling Fm
Regional extent
The formation is distributed essentially in the areas of the Eight Scenery Spots on West Hills, Mentougou District, Qianniantai, Panjiangou, Tanzhe Temple and Da’an Mts areas of western Beijing, as well as in the areas of Luanping, Pingquan, Xiabancheng and Xiahuayuan of Chengde City in northern Hebei. Its thickness varies greatly from place to place. In the western part of Beijing City the thickness of the formation is commonly of several meters to tens of meters. For instance, in the area of the Tanzhe Temple it is 30,80 m thick; at Dayu of Mentougou it is 35 m thick; at the Eight Scenery Spots on West Hills of Beijing it is 37 m thick; at the Qianniantai Flat it is 38-m thick; at Datai Flat it is 12 m thick. In the Pingquan-Xiabancheng region of northern Hebei its maximum thickness is of 610.9 m, while in the Xiahuayuan area its thickness is of 29.8m.
GeoJSON
Fossils
The formation yields plant fossils such as Todites denticulata, Stenis chinensis, Cladophlebis spp., Czekanowskia rigida, Podozamites lanceolatus and Phoenicopsis sp.; fish fossils such Xingshikous xishanensis; and “conchostracan” fossils as represented by Euestheria? sp.
Age
Depositional setting
Additional Information