Taergou Fm
Type Locality and Naming
The type section lies in the Taergou valley near Hongshanyao, 25−30 km west of Yongchang County, Gansu. It was named by Yuan Fuli in 1925.
Lithology and Thickness
Claystone. Lower part is of black shale intercalated with thin-bedded clayey limestone lenses and sandy shale intercalated with sideritic limestone; Upper part consists of dark-gray to black sandy shale and clayey shale, intercalated with fine-grained quartzite, with coal streaks in the top. Thickness 8.6 m or 14.2 m.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Hongshanyao Fm [NOT in Carboniferous Lexicon]
Upper contact
Conformable contact with the overlying Yanglucao Fm [NOT in Carboniferous Lexicon]
Regional extent
GeoJSON
Fossils
Contained in the limestone lenses are Brachiopods Chonetes carboniferus, C. granulifer transversalis, C. granulifer, C. latesinuata, C. latesinuata miaokouensis and C. semicircularis.
Age
Depositional setting
Additional Information
When the formation was named by Yuan, the thickness of Taergou given in the written description was 13.7 m while that in the section drawing was 8.6 m. In the written description it was said that the formation was composed of three layers of limestone, but actually only two layers: the other one is fossiliferous shale. Besides, this formation surveyed by Yuan and Liu successively can hardly be correlated.