Wulalik Fm
Type Locality and Naming
The type section is at Wulalikgou on the south slope of Gangder Hill, Inner Mongolia. The Wulalik Fm is derived from the Wulalik Bed proposed by Guan Shicong and Che Shuzheng in 1955. The reference section is at northern margin of youth farmland in Zhuozi Hill (An et al., 1990). The reference section is about 86 m thick.
Synonym: (乌拉力克组）
Lithology and Thickness
The formation is dominated by carbon-bearing siliceous shale of deeper setting, with black carbonaceous shale in the upper. At Hatugou-Lashizhong on the southern margin of Gangder Hill, the Wulalik Fm is 36 m thick.
Relationships and Distribution
Lower contact
It rests disconformably on the thin-bedded limestone intercalated with shale of Kelimoli Fm
Upper contact
It is disconformably overlain by green sandstone of Lashizhong Fm.
Regional extent
The lithology and thickness of the Wulalik Fm vary considerably along the length of its outcrop. At Hatugou-Lashizhong on the southern margin of Gangder Hill, the Wulalik Fm is 36 m thick, and is characterized by black carbon-bearing siliceous sediments. On the northern margin of youth farmland in Zhuozi Hill, it is about 86 m thick, and is composed of interbedded black carbonaceous and siliceous shale and thin-bedded limestone, with several siliceous or carbonaceous conglomerate beds in the lower-middle part. At Hanggaijing in Otog Qianqi, Inner Mongolia, and Hengshanbao in Lingwu County, Ningxia, the Wulalik Fm recorded a thickness of 183 m, and is dominated by black shale. In Tianchi, Ningxia, it is 52 m thick, and is composed dominantly of micrite.
GeoJSON
Fossils
This stratigraphic unit yields graptolites of Husterograptus teretiusculus assemblage, Nemagraptus gracilis assemblage and conodonts of Pygodus serra assemblage, Pygodus anserinus assemblage, in ascending order, and is equivalent or partially equivalent to the upper part of the Didymograptus murchisoni zone to Nemagraptus gracilis zone. In 1959, Mu Enzhi renamed the Wulalik Bed the Wulalik Fm, and studied the graptolites. In 1984, Chen Junyuan et al. restricted the Wulalik Fm to the graptolite Husterograptus teretiusculus zone.
Age
Depositional setting
Additional Information