Qianheishan Fm

The type section is located on the north slope of Qianhei Mt., Alxa Left Banner, Inner Mongolia. It was named by the No. 1 Gansu Party of Regional Geological Survey in 1974.

Sandstone and Limestone. Salt-bearing deposits of neritic lagoon facies, consisting of clastic rock and limestone. In the Heishan section, Lower member is composed of variegated sandstone intercalated with conglomerate and pebbly sandstone lenses, 23 m thick; Middle member is dominated by limestone, intercalated with thin-bedded calcareous siltstone and dolomitic limestone, containing brachiopods, etc., 25.2 m thick; Upper member consists of gray and brown-yellow calcareous quartz fine-grained sandstone (with cross beds well developed), intercalated with silty shale and limestone, containing conodonts, gastropods, fossil fishes and plants, 51.4 m. In areas such as Fulu Village of Jingtai, Gansu, it has stable lithology and gypsum interbeds, with limy lumpy conglomerate at bottom. In the Gantang area of Zhongwei, dolomitic limestone increases. Thickness 44−200 m.

The Middle member yields brachiopods Eochorisitella gansuensis, Schuchertella cf. gelaohoensis, Cleiothyridina sp., Composita sp., etc.; bryozoans Stenodiscus sp., Fenestella sp., etc.; the Upper member contains plants Sublepidodendron sp., Lepidostrobophyllum xiphidium, etc. Gao Lianda (1980) reported the spore Auroraspora-Lophozonotriletes assemblage of the formation found at Dashuigou of Jingyuan, below which was collected the element Kazakhstania sp. of the Kazakhstan Ammonoid Gattendorfia zone.

It is interpreted as a neritic lagoon facies, including gypsum