Weiyuanjiang Fm
Type Locality and Naming
Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences named this formation in 1975. The named section is located in Heping Township, Jinggu County, Yunnan Province. Original Weiyuanjiang Fm is a set of detrital rocks distributed in Simao and Jinggu area, Yunnan, which is between the Middle Triassic Choushui Fm and the Upper Triassic Dapingzhang Fm, dated as Carnian, Late Triassic. In 1983, the upper 5 to 6 beds of the Weiyuanjiang Fm (including 2 to 6 beds in the named Section), were classified by Xiong Jiayong and Liu Shirong, into the newly built Taozishu Fm. The revised Weiyuanjiang Fm only includes 2 to 4 beds in the original section, the age is early Carnian of the Late Triassic
Synonym:
Lithology and Thickness
Mainly dark gray, gray green mudstone, calcareous mudstone, calcareous argillaceous siltstone, feldspathic clastic sandstone with limestone, muddy limestone. The bottom is the complex conglomerate. Thickness is 593.5-611.6 m.
Relationships and Distribution
Lower contact
It is in disconformable contact with the underlying Choushui Fm of the lower Middle Triassic
Upper contact
It is in conformable contact with the overlying Taozishu Fm of the Upper Triassic.
Regional extent
Mainly distributed in Jinggu and Simao area of Yunnan Province. The lithology and thickness of the formation are basically stable and dominated by clastic rocks. In the Jinggu and Heping area, carbonate rocks have increased. To the east, there is a lack of carbonate rocks in the Dehua, Pu'er area.
GeoJSON
Fossils
Bivalves: Halobia parallelela, H. cf. bukowinensis, Posidonia bittneri, Pallaeonucula strigilata, Leptochondria sp., Burmesia sp.; Ammonoids: Protrachyceras sp., Longobardites cf. breguzzanus, Analcites cf. doleriticum; Plants: Equisetites arenaceous.
Age
Depositional setting
The formation is composed of littoral and shallow sea sediments
Additional Information