Dajianggang Fm
Type Locality and Naming
The type section is located in Shaoguo Village, Shuangyang County, Jilin Province, which was named by regional geological survey of Jilin Geological Bureau in 1978.
Synonym: The original lower Jurassic was named as “Erdaoliangzi formation” by Changchun College of Geology in 1960. But it was renamed as “Lower Permian” by the third team of Jilin coalfield geological exploration company survey team in 1971. In 1978, partial of “Erdaoliangzi formation” and “Lower Permian” were combined to a newly constructed Dajianggang Formation by regional geological team of Geological Bureau of Jilin.
Lithology and Thickness
The Dajianggang Fm is dominated slightly metamorphic greyish yellow, greyish green, yellowish grey, dark grey sandstone, siltstone, silty slate with intercalated tuffaceous conglomerate, tuff. Coal stems are occasionally occurred. Thickness is 645.1 m.
Relationships and Distribution
Lower contact
About 40 m yellowish grey conglomerate at the basal of this formation showed fault contact with the underlain Carboniferous Luquantun Fm
Upper contact
It is unconformity to the overlying Lower Jurassic Banshidingzi Fm
Regional extent
This formation is mainly westwards to eastwards distributed around the Dajianggang and Xiaoshipengzi, within the southern part of Shuangyang Basin, Jilin Province.
GeoJSON
Fossils
Plant: Glossophyllum, Cycadocarpidium, Drepanozarnites, Neocalamites
Age
Depositional setting
Fluvial-lacustrine-marsh facies
Additional Information