Daliugou Gr

North Qilian (north-central Gansu). The Daliugou Gr was named by the No. 5 Team of the Party of Regional Geological Survey, Gansu Bureau of Geology in 1977. The typical section is located in Daliugou of Sunan County, Gansu Province (south slope of Bansair Mountain).

Synonym: （大柳沟群）

The Daliugou Gr is a suite of carbonate rock interbedded with microclastic rock, which is subdivided into three lithologic members. Lower member is composed of gray and dark gray with minor yellowish gray to grayish green, crystallite limestone, dolomitic limestone, marl and purplish red rhythmic successions of shale, sandy slate and calcareous siltstone, with a layer of unstable conglomerate at the base. Middle member is purplish gray to purplish red, thick-bedded K-rich mudstone, clastic limestone interbedded with gray thick-bedded dolomitic limestone, dolomite intercalated with variegated calcareous slate, black carbonaceous slate and ferruginous quartzose sandstone, and boulder andesitic basalt. The lower part of the Upper member is variegated silty slate, calcareous argillite, siltstone and rhythmic beddings of limestone, gray-yellow marl and muddy slate; and its upper part is gray to purplish gray, medium-to thick-bedded dolomitic crystalline limestone, dolomite interbedded with yellowish gray pelitic limestone, greenish gray slate intercalated with lenses of conglomerate. Its thickness varies from 4384 to 5046 m (of which, the upper member is 1314 to 1788 m, the middle member, 2018 to 2152 m and the lower member, 1052 to 1106 m).

The upper and lower members yield microplants: Leiominuscula sp., Protosphaeridium sp., Trematosphaeridium holtedahlii, Trachysphaeridium sp., Leiosphaeridia sp. etc. In addition, the middle and lower members yield stromatolites Linella f.. etc. (Regional Geology of Gansu Province, 1989).