Xigou Gr
Type Locality and Naming
The type section is located at Xigou-Qinjiagou of Shuanghe, Songpan County, Sichuan. It was named by the No. 2 Regional Geological Survey Party of Sichuan Bureau of Geology in 1975, and used in The Regional Stratigraphic Scale of Southwestern China ⎯ Sichuan Volume (1978).
Lithology and Thickness
Limestone. Lower part consists of gray to gray-white thick-bedded crystalline limestone and oolitic limestone, with no fossils found; 51 m thick. Upper part is of gray-black cryptocrystalline limestone and bioclastic limestone, intercalated with black to gray-white dolomitic limestone bands, and containing abundant fusulinids; 35 m thick. Thickness thinning from east to west.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Xuebaoding Fm
Upper contact
Disconformable contact with the overlying Dongdahe Fm
Regional extent
Distributed mainly at Shuanghe of Songpan and Xiaozhaizi of Beichuan County. Also exposed in areas such as Shuiguanzi of Maowen County and Weigu of Heishui County
GeoJSON
Fossils
Upper part containing abundant Fusulinids Triticites parvulus, T. chinensis, Hemifusulina sp. and Schwagerina sp.
Age
Depositional setting
It is interpreted as platform neritic deposits
Additional Information