Xiangguletag Fm

The type section is at the area 1.5 km northeast of 996 highland southeast of Kawabulaktag in Shanshan County, Xinjiang. The Xiangguletag Fm was named by Xinjiang Compiling Group for Regional Stratigraphic Scale (1981). Following the naming of the Xiangguletag Fm, Xiao Bing (1981) used the term. The draft of the regional stratigraphic scale of Xinjiang came out informally in 1977, and Xiao (1979) also used the term. The time for the Xiangguletag Fm being published formally is available in the present book.

Synonym: (巷古勒塔格组). In Wuligeztag, it is represented by rhythms of thin-bedded limestone, calcareous mudstone, and was divided into Jinlonggou Fm and Xiaolongcha Fm by Wang et al. (1992).

The formation is represented by a sequence of variegated sandstone, siltstone, chert and calcareous shale intercalated with minor limestone, with phosphate nodules. In the type area, the Xiangguletag Fm is 182-423 m thick.

Trilobites Asaphus lepidurus and Phalacroma bexellei and brachiopod Stropomenidae have been found from the Xiangguletag Fm in the type area, and graptolites Phyllograptus anna, Cardiograptus yini, Isograptus divergens and trilobite Harpides troedssoni were also found from this stratigraphic unit in the vicinity of the type area. In Querquek, the Xiangguletag Fm is composed of calcareous shale, limestone in the lower part and black shale and chert in the upper part, and yields graptolites of Adelograptus-Kiaerograptus assemblage, D. (Expansograptus) abnormis assemblage, D. (E.) hirundo, Cardiograptus amplus assemblage, trilobites of Hysterolenus assemblage and conodonts of Cordylodus intermedius subassemblage (Wang Pu et al., 1992).