Huaitoutala Fm
Type Locality and Naming
The type section is located at Oulongbuluk Mt., west of the West Huaitoutala Coal Mine, Delingha City, Qinghai. It was named by Mu Enzhi et al. in 1958−1963.
Lithology and Thickness
Composed of clastic rock intercalated with limestone. The lower part of the Lower Member (layers 29−45) is dominated by gray, gray-green and gray-purple sandstones, intercalated with siltstone, shale and limestone, roughly corresponding to the Mn-bearing member of the former Huaitoutala Fm, 193 m thick; the upper part, dominated by gray and gray-black organic limestone and sandstone, intercalated with shale and coal streaks, 104.4 m thick. For the Middle Member (layers 46−56), the lower part consists of chert-bearing limestone and clastic limestone intercalated with sandy shale, 65.1 m thick; the upper part, of gray thin-bedded limestone and organic limestone intercalated with sandstone and shale, 217 m thick. Upper Member (layers 57−65) is composed of gray to gray-black clayey bioclastic limestone and clayey limestone with bioclastic intercalated with clayey chert banded limestone, siltstone, shale, etc., 124 m thick.
Westward to the Nanshan area at the middle sector of Saishiteng Mt., the upper part of the formation turns into volcanic rock, pyroclastic rock intercalated with organic limestone, and the lower part consists of clastic rock; totaling 1367 m thick.
Relationships and Distribution
Lower contact
Conformably on the underlying Chengqianggou Fm
Upper contact
Disconformable contact with the overlying Keluk Fm (not in Lexicon; but may be synonymous with the Hurleg Fm)
Regional extent
GeoJSON
Fossils
Lower Member's lower part yields Brachiopods Antiquatonia insculpta-Gigantoproductus moderatiformis assemblage, and upper part contains Corals Thysanophyllum-Dorlodotia mui assemblage of the middle Visean Age.
Middle Member's lower part contains the Corals Gangamophyllum spiroidea-Orionastraea philipsi assemblage and Brachiopods Giganotoproductus latissimus-Kansuella kansuensis assemblage, and upper part contains the Corals Lithostrotion qinghaiense-Cithostrotion irregulare var. asiaticum assemblage and Brachiopods Gigantoproductus geniculatus-Echinoconchus punctatus assemblage, corresponding to the Yuanophyllum zone of the Shangsi Fm in South China.
Upper Member contains the Corals Aulina rotiformis-Lithostrotion irregulare assemblage and Brachiopods Gigantoproductus edelburgensis-Semiplanue Semiplanus assemblage, of the Serpukhovian Age
Age
Depositional setting
It is interpreted as marine-continental deposits
Additional Information