Balunsuo Fm
Period:
Paleogene
Age Interval:
Late Eocene , (12b)
Province:
Inner Mongolia
Type Locality and Naming
Central-Eastern Inner Mongolia. The naming section is located at the east end of the Baron Sog platform in the southern part of the Xar Moron area, Inner Mongolia. Named by H.T. Chang in 1930.
Synonym: Baron Sog Fm
Lithology and Thickness
Consists of light gray mudstone and fine sandstone with cross bedding, locally containing white marly concretions. This bed is just the “upper white bed” in the related section described by H.F. Osborn in 1929. Its maximum thickness is up to 9 m.
Lithology Pattern:
Sandy claystone
Relationships and Distribution
Lower contact
This formation is in disconformable contact with the underlying Middle Eocene Wulangechu Fm (Ulan Gochu Fm).
Upper contact
Regional extent
GeoJSON
null
Fossils
The formation yields the mammals Embolotherium ultimum, Schizotherium avitum and Schizotherium sp.
Age
The age of this formation was suggested to be Early Oligocene in the past, but Wang et al. (2019) inferred it was Late Eocene. [China Lexicon column for Paleogene implies only mid Priabonian]
Age Span:
Beginning stage:
Priabonian
Fraction up in beginning stage:
0.2
Beginning date (Ma):
36.95
Ending stage:
Priabonian
Fraction up in the ending stage:
1.0
Ending date (Ma):
33.90
Depositional setting
Depositional pattern:
Additional Information
Compiler:
Tao Deng, Yuanqing Wang, Qian Li, et al.