Xiwangmiao Fm
Type Locality and Naming
The type locality of the Xiwangmiao Formation is located at Limahe village, Guanhe Township, Huili City, Liangshan Yi Autonomous Prefecture, Sichuan Province. No type section is assigned when Zhang et al. (1958) erected the unit. An auxiliary section, Dacaohe section, was proposed by Gu and Liu (1997) as representative section of the formation. This section lies between Taoziping and Qiaowo villages in Dacaohe River Valley, Puge County, Liangshan Yi Autonomous Prefecture, Sichuan Province (102°25’00”E, 27°28’05”N), about 6.7 km southwest of the seat of Qiaowo Town, or about 16 km northwest of the seat of Puge County. It was measured by the Sichuan First Regional Geological Survey Team in 1963. The formation was named by Zhang et al. (1958). The name is derived from Xiwangmiao Temple, about 5 km north of the seat of Huili City, Liangshan Yi Autonomous Prefecture, southwestern Sichuan Province. Originally the unit was called Xiwangmiao Bed by Zhang et al. (1958), and was renamed Xiwangmiao Formation by Sichuan First Regional Geological Survey Team (1965).
Synonym: （西王庙组）
Lithology and Thickness
The Xiwangmiao Formation is a clastic sequence, known as “red bed” or “upper red bed” It is dominated by purplish red, brick red and green thick-bedded calcareous quartzose siltstone and sandy mudstone, with interbeds of fine-grained calcareous quartzose sandstone, limestone, dolomite, and gypsum. In this section, the formation is 251.6 m thick.
Relationships and Distribution
Lower contact
The Xiwangmiao Fm is in conformable contact with the underlying Toupossu Fm. Its lower and upper boundaries are defined by lithologic changes as both the top of underlying Toupossu Formation and the base of overlying Loushankuan Formation are dolomites.
Upper contact
The Xiwangmiao Fm is in conformable contact with the overlying Loushankuan Fm. Its lower and upper boundaries are defined by lithologic changes as both the top of underlying Toupossu Formation and the base of overlying Loushankuan Formation are dolomites.
Regional extent
The Xiwangmiao Formation is exposed in the Yangtze Area of Souh China Region, restricted to the border area between northeastern Yunnan Province and southwestern Sichuan Province, i.e., in the west part of Yangtze Area of South China Region. The formation is stable in stratigraphical horizon, but slightly varies in both lithology and thickness. In the area of Huili and Puge counties, southwestern Sichuan Province, the red clastic strata reach up to about 250 m thick. Northward to the area of Yuexi and Ganluo counties, also in Sichuan, thin interbeds of para-dolomitic limestone occur within the red clastic strata whereas the thickness reduced to 80‒90 m; In the areas along both banks of Jinshajiang River, northeastward from Qiaojia (Yunnan) to Jinyang (Sichuan), Yongshan (Yunnan) and Leibo (Sichuan), the formation is usually 150‒174 m thick, occurring intermittently gypsum beds or lenses that are intercalated within the dolomitic limestone; In the area of Huidong and Ningnan counties, southwestern Sichuan, the formation changes in facies, becoming red micritic dolomite and marlstone with a thickness of 170‒180 m.
GeoJSON
Fossils
No fossil is found from this formation yet.
Age
Depositional setting
The formation represents deposits in tidal flat and supratidal flat sedimentation in a hot and dry climate.
Additional Information