Baogedawula Fm
Type Locality and Naming
Central Inner Mongolia. The type section is located at Zhurihe (E114°35′, N44°08′), about 3 km north of the Baogedawula (=Baogeda Ula) hill and 50 km northwest of Abagaqi town, Xilinhot City, central Nei Mongol. A reference section is located at Damiao (E111°32′, N42°03′), Siziwang Qi County, Nei Mongol (BGMRNMAR, 1996). It was formally published by the Bureau of Geology and Mineral Resources of Nei Mongol Autonomous Region (BGMRNMAR) (1991).
Synonyms: Baogeda Fm, Baogeda Ula Fm; The Baogedawula Fm was once included in the Abagaqi Fm or Sigeermiao Fm (Zheng et al., 1999). BGMRNMAR (1996) considered the Shangdu Fm as a synonym of the Baogedawula Fm.
Lithology and Thickness
The Baogedawula Fm is characterized by a series of greyish-green, brick-red, and brownish-red mudstones, sandy mudstones, and siltstones interbedded with greyish-white limestones and blackish-green basalts. It contains fossil ostracods, gastropods, and abundant mammals, especially the elements of “Hipparion fauna” common in the Neogene of North China. Its thickness is more than 25 m.
Relationships and Distribution
Lower contact
In the type section, the Baogedawula Fm disconformably contacts with the underlying Miocene Tongguer Fm (=Tung Gur Fm) or the Damiao Fm (a synonym of the Tongguer Fm).
Upper contact
In the type section, the Baogedawula Fm is disconformably overlain by the Pleistocene Abagaqi Fm. T. Deng et al. (2019; Neogene chapter of China Integrated Stratigraphy and Timescale) show the Ertemte Fm Bed (currently in Column 12) as both younger and overlying the Baogeda Ula Fm; rather than equivalent in age as given in the older China Lexicon.
Regional extent
The formation is widely distributed in area of Abaga Qi, Chagan Nor, Wulagai, Sonid Zuoqi, and Sonid Youqi, central Nei Mongol. The thickness of the Baogedawula Fm varies from more than 25 m in Damiao-Bulutaimiao area, more than 40 m in Sonid Zuoqi-Sonid Youqi area, ~5m in Talaqin Tala, and close to 50 m in the Wuchuan Basin.
GeoJSON
Fossils
Mammals: Erinaceidae indet. 1, Erinaceidae indet. 2, Parasoriculus sp., Myomimus cf. M. sinensis, Dipoides mengensis, Sicista bilikeensis, Lophocricetus xianensis, Paralactaga parvidens, Brachyscirtetes tomidai, Dipus farudator, Rhinocerodon abagensis, Sinocricetus zdanskyi, Nannocricetus primitivus, Kowalskia shalaensis, Microtoscoptes fahlbuschi, Abudhabia abagensis, Prosiphneus eriksoni, Hansdebruijnia perpusilla, H. pusilla, Karnimatoides hipparionus, Micromys chalceus, Parahizomys hipparionum, Ochotona cf. O. lagreli, Promephitis sp., Pekania palaeosinensis, Hyaenictitherium hyaenoides, Hipparion (Baryhipparion) tchikoicum, Rhinocerotidae indet., Giraffidae indet., Gazella sp. 1, Gazella sp. 2. (Qiu and Wang, 1999; Qiu and Li, 2016; Sun et al., 2018).
Age
Depositional setting
It is interpreted as a river-lake environment.
Additional Information