Manghuai Fm
Type Locality and Naming
The type section is located in Shantou Street, Bushuai Village, Yun County, Yunnan Province.
Synonym: Minghuai Fm. The former Fenghuai Fm is a set of clastic rock and acid volcanic rock assemblages distributed in Jingdong area of Yunxian County, Yunnan Province. The age of the Lower Member of the Fenghuai Fm (mainly clastic rock and containing bimolar Costatoria goldfussi) was determined by Yunnan Bureau of Geology and Mineral Resources in 1990. In 1992, Chengdu Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences and Sichuan Bureau of Geology and Mineral Resources Regional Survey, although using the revised lithostratigraphic range of the Minghuai Fm, the age of the Minghuai Fm was determined as the Middle Triassic Anisian. This Lexicon follows the 1990 Yunnan Bureau of Geology and Mineral revision.
Lithology and Thickness
It is composed of thick layers of purplish-gray massive rhyolite, rhyolite breccia tuff interbedded with shale, and volcanic breccia and sandy conglomerate appear at the bottom. Thickness is 1127 m.
Relationships and Distribution
Lower contact
It is in pseudo-conformable contact with the underlying Shanglan Fm.
Upper contact
It is in pseudo-conformable contact with the overlying Xiaodingxi Fm. The formation is unconformable over the Permian stratum.
Regional extent
This formation is mainly distributed in the Lancang River valley in Jingdong area of Yunxian County, Yunnan Province. The lithology and thickness of the formation are changed significantly. The lava in the Fenhuai area is increased and thickened significantly, reaching 2739.6 m. In the west of the named section, the thickness of the section is 118.8 m at Zijiacun and 658.9 m at Binlinghekou. In the north, the thickness of dacite, quartz porphyry and tuff is increased with the thickness of 140~800 m at Maomaohe in Jinggu County.
GeoJSON
Fossils
Age
Depositional setting
Marine facies
Additional Information