Batamayineishan Fm

The type section is at Batamayinei Mt. of southeastern Kalamaili Mt., Qitai County, Xinjiang. It was named by Xijiang Party of Regional Geological Survey in 1964, and formally cited in Regional Stratigraphical Scale of Xinjiang in 1981.

Volcanics. A continental volcanic rock series, including volcanic rocks and clastic rocks hosted in them that have been erupted with Liugeshu and the East and West Heshan Mts. as the centers. In Batamayinei Mt. located in the center of eruption, the rocks are dominated by andesitic porphyrite and basaltic porphyrite, intercalated with large amounts of acidic felsite, perlite and pyroclastic rock, and divided into three eruption cycles by the red round conglomerate layer, the tuffaceous conglomerate and the sandy mudstone. On the outer side the formation usually consists of two rock members, the middle-lower member is intermediate-basic lava, the upper is dominated by intermediate-acid pyroclastic rock. Eruption unconformity occurs between the two members, and there are only very few sedimentary clastic rock interbeds. Thickness of the formation reaches 4000 m.

The formation on the boundary of the eruption zone is dominated by sedimentary clastic rocks. In the vicinity of Shuangjingzi, the lower member consists of tuff, variegated sandstone and mudstone, 230 m thick; the upper member of gray-green conglomerate intercalated with andesite, sandstone, mudstone and coal seams, 115 m thick. Yuan Fuli called the upper member the “ridge boulder conglomerates”.

The Angaropteridium-Mesocalamites floral assemblage, with the main elements of A. ligulatum, M. cistiformis, Belonophyllum acriculum, etc. The spore-pollen assemblage in the black shale of the upper member is characterized by 80% of Gymnosperm spore-pollen, in which autoblast pollen Endosporites is most abundant, rib-bisaccate pollen accounts for 3%, dominated by Striatolebachites? sp., while fern spores only 20%.

It is interpreted as a continental volcanic eruption facies

The ⁴⁰Ar/³⁹Ar age of whole argon releasing for basalts at Xidagou, Dishui Spring is (306.05+1.18) Ma, and the platform age is (282.5 ±3.2) Ma.