Lamei Fm
Type Locality and Naming
The first area survey team of Yunnan Geological Bureau named it in 1977. The named section is located in Lamei Village, west bank of Jinshajiang River, Lijiang County, Yunnan Province. In 1947, P. Misch named the Lower Triassic marine clastic rocks around Lijiang of Yunnan as "Lijiang layer". And in 1962, Zhao Jinke et al. renamed it as "Lijiang group". In order to distinguish the Tertiary "Lijiang breccia" developed in Lijiang, the First Area Survey Team of Yunnan Geological Bureau renamed this set of strata as the Lamei Formation in 1977, which has the same meaning as "Lijiang Group". In 1990, Yunnan Bureau of Geology and Mineral Resources redefined the meaning of the Lamei Formation, which was only the upper horizon of the original formation, and its age was defined as the Early Triassic Olenekian. This lexicon follows it.
Synonym:
Lithology and Thickness
They are mainly yellow and yellow-green containing glauconite siltstone, mudstone, oolitic limestone and limestone. The thickness is 166 to 490 m.
Relationships and Distribution
Lower contact
The bottom boundary is marked by yellow-green glauconite-rich sandstone and concordant contact with the underlying Luguhu Fm of the Lower Triassic.
Upper contact
The top boundary is also marked by yellow-green glauconite-rich sandstone.
Regional extent
They are mainly distributed in the north of Heqing County, Lijiang, Ninglang, eastern Zhongdian and southwestern Yanyuan of Sichuan
GeoJSON
Fossils
The fossils are dominated by bivalves, which is Eumorphotis inaequicostata-Pteria ussurica assemblage zone.
Age
Depositional setting
The formation is shallow water deposit.
Additional Information
In 1983, Chen Dingchang called this set of strata Zuosuo Formation.