Luguhu Fm
Type Locality and Naming
The type section is located at the north bank of Lugu Lake of Yanyuan County, Sichuan. It was named by Chen Dingchang in 1983.
Synonym:
Lithology and Thickness
It is dominated by purple-red sand and shale, with unstable dolomite and oolitic limestone, and yellow-green mudstone in the lower part. The bottom is generally marked by basaltic bottom conglomerate with a thickness of 1-30 m. Its thickness is 400～500 m.
Relationships and Distribution
Lower contact
It is conformable in contact to the underlying Upper Permian Heinishao Fm
Upper contact
It is conformable in contact to the overlying Lamei Fm
Regional extent
This formation is mainly distributed in the north of Heqing County, Yunnan, Lijiang, Ninglang, east of Zhongdian, and southwest of Yanyuan, Sichuan. In the Lijiang and Heqing areas, the bottom is a conglomerate layer with a thickness of about 10 m, which is in disconformable contact with the underlying Upper Permian.
GeoJSON
Fossils
It was yielded abundant bivalve fossils, which can be divided into the Pseudoclaraia wangi assemblage for the lower part and Eumorphotis multiformis assemblage for the upper part.
Age
Depositional setting
It is interpreted as shallow marine environment.
Additional Information
In 1947, P. Misch named the Lower Triassic marine clastic rocks in Lijiang, Yunnan as the "Lijiang Bed", and in 1962, Zhao Jinke and others renamed it as the "Lijiang Group". In order to distinguish the Tertiary "Lijiang breccia" developed in Lijiang City, in 1977, the first area survey team of the Yunnan Geological Bureau renamed this set of strata as the Lamei Formation, which has the same meaning as the "Lijiang Group". In 1983, Chen Dingchang further divided this set of strata into the Zuosuo Formation (the Lamei Fm in this lexicon) for the upper part of this group and the Luguhu Formation for the lower part of this group, separately representing the early Triassic Olenekian and Induan deposits in the Lijiang area.