Daqiaodi Fm
Type Locality and Naming
The type section is located at Baoding, 30-40 km southwest of Dukou City, Sichuan Province. Reference section is location on Nalajing, Yongren, Yunnan Province. Reference section is located on Nalajing, Yongren, Yunnan Province.
Synonym: Daziaodi Fm. It is named “Nalajing Coal Beds” at the beginning, including “Purple Bed in Bingnan area”, “Taojiadu Bed” “Dadiqiao Bed” and “Dajing Bed” in ascending order. Later, in the year of 1957, “Dadiqiao Bed” changed to Dadiqiao Fm by Yunnan Geological Bureau which belongs to late Triassic.
Lithology and Thickness
It is mainly composed of gray, gray-green, gray-black, yellow-green conglomerate, sandstone, siltstone, mudstone, shale, and coal seams.
Relationships and Distribution
Lower contact
The bottom is in integrated contact with the purple-red argillaceous limestone at the top of the underlying Bingnan Fm
Upper contact
The top is in pseudo-integrated contact with the overlying Baoding Fm
Regional extent
The lithology of this group is relatively stable, and it is widely distributed in Nalaqing, Baoding, Taipingchang, Longtan Daqiaodi and Huaping in the west of Dukou City; Baoding area is the most developed area with a thickness of 2156 m; Yanbian Hongni and Mi. The Yisantan area is only 676 m thinner.
GeoJSON
Fossils
Plant fossils include: Equisetites arenaceum, Danaeopsis marantacea, Pecopteris callipteroides, Pterophyllum longifollium, Ctenozamites chinensis, Pachyopteris yungiensis, Rireticopteris microphylla, and vertebrate fossil Himalayasaurus tibetensis. In Yongren, Yunnan, marine bivalves were also found in this group.
Age
Depositional setting
Additional Information