Liguan Fm
Type Locality and Naming
The type section is located at Liujiacun Village in Liguan Township, Linyi City, Shandong Province (118°23’ 40”E, 35°16’26”N), lying about 1.3 km west of the Liguan Town, or about 19 km north of the Linyi City. In this section the formation is 29.94 m thick. The Liguan Formation was named by Liang (1980). The name is derived from Liguan Township in Lanshan District, Linyi City, southern Shandong Province. Liang (1980) established the formation to replace the Wushan Fm because the latter formation shares the same Latinized and phonetic name with the earlier established Permian Wushan Limestone in eastern Sichuan (now in Chongqing Municipality) (Blackwelder, 1907) and the Neoproterozoic Wushan Fm in Anhui Province (Li, 1939). Originally the Cambrian part of “Wushan Formation” included two lithologic intervals with the interval of quartz sandstone in the lower part and the limestone interval in the upper part. Zhang et al. (1994) restricted the Liguang Formation to the lower sandstone interval by excluding the upper limestone interval that is actually a northeastward extension from the type locality of the overlying Chushatung Fm.
Synonym: （李官组）
Lithology and Thickness
The Liguan Formation is a clastic sequence, dominated by grey moderately thick-bedded quartz sandstone and is also composed of brick-red, and yellowish green mudstone and sandy shale as well, with glauconite and peudocrystal of halite throughout the whole formation and greyish purple breccia at the base.
[Figure: Stratigraphic column of the Liguan Formation, Tangtou section that lies in the type area of the Liguan Formation, about 5 km south of the Liguan Town, Linyi, western Shandong Province. A, Outcrop of the Tangtou section, showing the Tongjiazhang Fm, the Liguan Fm, and the Zhushadong Fm and their contact relationship; B, close-up view of the red siltstone (the yellow box on A) near the base of the Liguan Formation; the red arrow pointed its stratigraphic position in the section (modified from Li et al., 2020)]
Relationships and Distribution
Lower contact
The Liguan Fm rests disconformably on either the Tumen Gr of the Ediacaran System or the Tongjiazhuang Fm of Tonian System.
Upper contact
It is conformably overlain by the Chushatung Fm.
Regional extent
The Liguan Formation is exposed only in the Western Shandong Area of North China Region, restricted to the Linyi area, with thickness ranging usually between 20 and 40 m, occasionally reaching to 60 m.
GeoJSON
Fossils
No fossils have been found from the formation yet.
Age
Depositional setting
The formation represents littoral beach sedimentation setting.
Additional Information