Shiqiantan Fm

The type section is located at Shiqiantan, east of Jiangjunmiao, Qitai County, Xinjiang. It was named by Yuan Fuli in 1948.

Siltstone and Limestone. A suite of neritic clastic rock and limestone formation. Lower clastic rock Huxingliang Member comprises gray-green fine- to medium-grained conglomerate and clayey siltstone intercalated with sandy limestone, 868 m thick at Huxingliang, thinning westward and pinching out at Kushuigou. Middle limestone Shuangjingzi Member is composed of light-gray limestone intercalated with 4−5 layers of bioclastic micritic limestone, not exceeding 50 m in the area north of Shiqiantan, pinching out westward to Kushuigou, and mixed up eastward with the overlying Pingliang green mudstone Member, being composed of gray-green clayey siltstone intercalated with pebbly sandstone, sandy limestone and marl. Upper green mudstone Pingliang Member is confined in the area west of Shengligou and south of Tamugang, consisting of dark-gray silty mudstone intercalated with sandstone, fine-grained conglomerate and limestone lamellas, 250 m thick, and dominated by red mudstone westward to Liukeshu. The thickness of the middle and upper members increases from 500 m to over 1600 m.

The rich fossils are mainly produced from the Shuangjingzi limestone member. The middle and upper parts yield Fusulinids Profusulinella paratypica, P. parva, Pseudostaffella irinovkensis, etc.; Conodonts Idiognathodus delincatus, Streptognathodus parvus, etc.; Ammonoids Diaboloceras sp., Owenoceras sp., Syngastrioceras sp., etc. The lower part contains Conodonts Streptognathodus Str. erectus, Str. junggarensis, etc.

It is interpreted as neritic clastics and limestone