Kedao Fm
(21), mid-Middle Permian
Type Locality and Naming
The type section is located at Kedao 6 km to the southeast of Kaishantun, Longjing City, Jilin Province, and the reference section is situated in a Temple Cave in the area of the Kaishan Village, Longjing City. It was named by Yang Qilun, Li Xikun in 1963, and was cited officially by the Compiling Group on the Regional Stratigraphic Chart of Jilin Province.
Lithology and Thickness
Conglomerate and clastics. Representing a suite of grey, purple and grey-black tuffaceous sandy conglomerates, intercalated with chloritized andesite and limestone lenses. The pebbles contained in the conglomerate are mainly of marble, limestone, volcanic lava and tuff composition, among which the former two kinds of pebbles yield Fusulinida and other fossils. The basal part consists of grey tuffaceous conglomerate. The upper part represents a suite of grey-green and grey-purple schistose tuffaceous sandstone and slate, intercalated with light-blue-green tuffaceous slate and pebble-bearing coarse-grained sandstone. Total thickness is over 1800 m.
Relationships and Distribution
Lower contact
Disconformable contact with the underlying Miaoling Fm
Upper contact
Disconformably overlain by either the Qinggouzi Fm or the Kaishantun Fm
Regional extent
Distributed extensively, from the Kaishantun area of Longjing City in the southern part (with a thickness of 852 m), extending northerly to the areas of Xidapuo, Tianqiao Ridge, Miaoling Ridge (with a thickness of over 1425 m) and Liangzichuang (with a thickness of 1682 m) with the thickness increasing, with the volcanic substance reducing in amount, with the granularity getting smaller, and with the limestone intercalations being the thickest in the Miaoling area, and being thinner in the area of Hunchun City.
GeoJSON
Fossils
The pebbles yield Fusulinida as represented by Neoschwagerina, Verbeekina, Yabeina and Schwagerina.
Age
Depositional setting
The lower part of the formation is composed of shallow-sea coarse clastic rocks, which are gradually transitioning upwards to continental deposits.
Additional Information