Luofengxi Gr
Type Locality and Naming
The type section is at Luofengxi 10 km west of Weifang, western Fujian. The Luofengxi Gr is derived from the Luofengxi Phyllite proposed by Wang Shaowen in 1931.
Fujian Party of Regional Geological Survey (1982) divided it into three groups, the Weifang Gr and Dongkengkou Gr in the lower part, and Luofengxi Gr in the upper part, a suggestion followed by Fujian Bureau of Geology and Mineral Resources (1985). In 1991, Zhu Yulin considered the lower part of the redefined Luofengxi Gr to be Early Ashgill.
Synonym: (罗峰溪群）
Lithology and Thickness
The Luofengxi Gr is divided into two members. Lower member, 685-744 m thick, is represented by interbedding of thin-bedded metamorphosed argillaceous chert, metamorphosed chert and carbonaceous phyllitic mudstone or phyilltic siltstone. Upper member recorded an incomplete thickness of 839 m, and is composed of gray thick-bedded metamorphosed quartz sandstone intercalated with metamorphosed siltstone and muddy slate.
Relationships and Distribution
Lower contact
It overlies the Dongkengkou Gr (Dongkengkou Fm) of late Cambrian in the type section. However, regionally, the next older unit is the Weifang Gr of early through middle Ordovician
Upper contact
The upper member is unconformably overlain by the Upper Devonian.
Regional extent
GeoJSON
Fossils
The lower member yields chitinozoan Conochitina elegans, Lagenochitina sp., Desmochitina sp., D. moyensis, Rhabdochitina sp., Cyathochitina sp. and sporopollens Leiofusa sp., Veryhachum sp., Leiosphaeridia sp., Lophominuscula sp.
Age
Depositional setting
Additional Information