Yangbulak Fm

The type section is located at Yangbulak, Mori County, Xinjiang. It was named by Gao Yunsheng et al. in 1970.

Volcaniclastics, Volcanics and Sandstone. Neritic eruptive basic-acid pyroclastic rock, lava and tuffaceous sandstone intercalated with bioclastic rock. Around Yangbulak, it is composed of purple tuffaceous sandstone and tuffaceous calcareous sandstone-conglomerate intercalated with feldspar-porphyry, quartz porphyry and andesitic dacite-porphyry. Exposed thickness 1047 m. In general, from west to east, the exposed area becomes larger, lavas increase and contain fossils.

Extending eastward to north of Baopikou, it is dominated by gray-green volcanic tuff and tuffaceous sandstone occurring alternatively, intercalated with amygdaloidal basalt-porphyrite, massive andesite and felsite, with normal clastic rock and grit in the lower part while sandstone, siltstone, pebbly grit and conglomerate in the middle part. In the upper part there are bioclastic limestone and crinoid stem-bearing crystalline limestone. There, it is in faulted contact with the underlying Shaleisaierk Fm while the top is unseen. Exposed thickness 2979.6 m.

North of Baopikou, the upper limestone contains Brachiopods Dictyoclostus sp., Linoproductus simerensis and Krotovia sp.; Corals Lophophyllidium sp. and Cystodendropora sp.; Bivalve Aviculopecten sp.

It is interpreted as a volcanism erupting into a neritic setting.