Baoraobao Fm
Type Locality and Naming
The type section is located at Baor’aobao of the Hardatesumu area, Sunite Left Banner, Inner Mongolia. It was named by Zhu Guangli in 1965, and was officially cited in the "North China Paleontological Atlas-Inner-Mongolian Pamphlet" (1976).
Synonym: Baor'aobao Fm
Lithology and Thickness
Volcaniclastics. Lower part is black-grey tuffaceous siltstone, intercalated with thick-bedded conglomerate, locally with volcanic rocks. Middle part is interbeds of grey-green greywacke feldspar-rich sandstone and silty slate, with its base being composed of dark-grey massive metamorphosed conglomerate, intercalated with silty slate. Upper part consists of grey-green blue-green and purple massive sandy conglomerate, intercalated with indigo-purple rhyolitic dacite and green greywacke. The basal part of the type section has been intruded by quartz-porphyry. The thickness of the formation is over 3725 m.
Relationships and Distribution
Lower contact
Unconformable contact with the underlying Xiujimqin Fm (Xiwuzhumuqinqi Fm).
Upper contact
Next younger regional unit (diachronous contact) is the Linxi Fm.
Regional extent
The formation is distributed in the Baor’aobao and Changtusili County of Sunite Left Banner, the Baogedawula of Abaga Banner; the Abahanar Banner; the Baolige of Dongwuzhumuqin Banner; the Baoligexinguole, Harigentai and Hanwula of the Arshan Mt., Xinwuzhumuqin Banner. This formation has less changes in its lithology, and its thickness is getting progressively thinner from the Hanwula area towards both the eastern and western sides of the region.
GeoJSON
Fossils
Bivalves represented by Palaeanodonta, Palaeomutela and Oligodon
Plant fossils represented by Callipteris, Shenshuensis, Calamites, Comia, Sphenopteris and Rhipidopsis.
Age
Depositional setting
It is interpreted as a continental volcaniclastic rock formation.
Additional Information