Duozishan Fm
Type Locality and Naming
Southeast Liaoning. The Duozishan Fm was named by Yu Jianzhang (C. C. Yu), Cui Shengqin and Qiu Ganlin in 1964. The typical section is situated in the Yongning basin of Fuxian County and the reference section is in Xihai'an to Dashitougou in Yongning, Fuxian County, Liaoning Province. Middle formation of Yongning Gr.
Synonym: （朵子山组）
Lithology and Thickness
The Duozishan Fm is dominated by the multilayered rhythmites composed of purple, thick-bedded polymictic conglomerate intercalated with grayish purple or pink coarse-grained feldspathic graywacke. The thinnest rhythmite is about 20 m thick and the thickest is more than 100 m. The polymictic conglomerate is composed of chert, stromatolites-bearing chert, quartzite, igneous rock and ferruginous breccia. The total thickness is about 1514 m thick.
Relationships and Distribution
Lower contact
It rests conformably on the underlying Songshu Fm
Upper contact
Regional extent
The Duozishan Fm is restricted to the Yongning Basin in Fuxian County, and Laotieshan to Shanggou in Luda area.
GeoJSON
Fossils
Age
Depositional setting
The Duozishan Formation is considered to be a molasse formation during geosynclinal inversion (by Yu Jianzhang et al., 1958). However, Lin Weixing et al. (1984) considered that it is probably transition sediments from the river to the littoral delta facies.
Additional Information