Xuniwusu Fm
Type Locality and Naming
It was named by Hu Xiao, Niu Shugen and Zhang Yintau in 1987. The type section is located at Bainaimiao, Siziwang Banner, the Inner Mongol Zizhiqu.
Synonym: (徐尼乌苏组)
Lithology and Thickness
The formation is represented by a suite of fine-grained upwards flysch succession. The lower part of the formation is dominated by coarse sandstone containing pebbles, coarse-grained graywacke and medium to fine grained sandstone, together with the silty mudstone and limestone to form a rhythmical succession. The upper part is composed of medium to fine grained sandstone and siltstone. It is 1100 m in thickness.
Relationships and Distribution
Lower contact
The Xuniwusu Fm is underlain by the lower metavolcanic rock series of the Bainaimiao Gr in locally low-angular disconformity, or pseudo-conformity.
Upper contact
It is disconformable overlain by the Xibiehe Fm (the Naqing Fm).
Regional extent
It is, as so far known, exposed only in the area of Bainaimiao, Siziwang Banner, the Inner Mongol Zizhiqu.
GeoJSON
Fossils
The limestone bears anthozoa Favosites, Squameofavosites, Heliolites, Thamnopora, Halysites (Acanthohalysites), Mesofavosites?, etc.
Age
Depositional setting
Flysch strata
Additional Information