Youganwo Fm
Type Locality and Naming
The naming section is located near Youganwo, Maoming, Guangdong. Named the Youganwo bed by Chen Guoda in 1948 and renamed the Youganwo Formation by Pei Wenzhong et al. in 1963.
Lithology and Thickness
Lower member is grayish white or grayish green, fine sandstone, siltstone, muddy sandstone, sandy mudstone and mudstone, occasionally intercalated with sandy conglomerate, the upper part of which is intercalated with carbonaceous shale and 1–4 beds of lignite. Upper member is brown and blackish brown oil shale, with 1–7 beds of lignite and locally with clay, fine sandstone, carbonaceous shale and marlstone. The total thickness is ~120 m.
Relationships and Distribution
Lower contact
Unconformable contact with the underlying Cretaceous (which is the Tongguling Fm in this Maoming Basin)
Upper contact
The formation has a disconformable contact with the overlying Huangniuling Fm.
Regional extent
It is mainly distributed in the Maoming basin, Guangdong.
GeoJSON
Fossils
The formation contains such ostracods as Limnocythere sp., Pontocypris sp. and Cytheridea sp. The vertebrate fossils were collected from the upper member, mainly including Cyprinus maomingensis, Anosteira maomingensis, Aspideretes impresus, Isometremys lacuna and Tomistoma petrolica.
Age
Depositional setting
It is lacustrine-swampy deposits bearing combustible organic rock.
Additional Information