Xiliugou Fm
Period:
Paleogene
Age Interval:
Eocene, (6c)
Province:
Gansu
Type Locality and Naming
Lanzhou-Xining region. The Regional Survey Party of the Gansu Bureau of Geology designated a sequence of mainly fluvial deposits in the first rock unit of the original Xianshuihe Fm in the Lanzhou basin as the Xiliugou Formation in 1984. The naming section is located in an area from Yehucheng to Fenghuang Village, Yongdeng County, central Lanzhou basin, Gansu.
Lithology and Thickness
Dark red, massive pebbly sandstone and grit with thin-bedded mudstone. The thickness is 59–593 m.
Lithology Pattern:
Conglomerate
Relationships and Distribution
Lower contact
Upper contact
It has a conformable contact with the overlying Paleogene Yehucheng Fm.
Regional extent
This formation is distributed in the Lanzhou basin and Longzhong basin.
GeoJSON
null
Fossils
It yields the ostracods Cypris and Eucypris and the charophytes Stephanochara and Harrisichara.
Age
China Lexicon chart had shown as span of entire Eocene; but revised basal age of overlying Yehucheng Fm implies span is now earliest Eocene.
Age Span:
Beginning stage:
Ypresian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
56.00
Ending stage:
Ypresian
Fraction up in the ending stage:
0.7
Ending date (Ma):
50.45
Depositional setting
Depositional pattern:
Additional Information
Compiler:
Tao Deng, Yuanqing Wang, Qian Li, et al.