Sanqushan Fm
Type Locality and Naming
The type section is at Huipu-Songfan southwest of Changshan City, Western Zhejiang. The Sanqushan Fm is derived from the Sanqushan Limestone proposed by Sheng Xinfu (1951). Following the naming of the Sanqushan Limestone, Lin Baoyu and Zou Xinhu (1977) restudied the type section, and renamed the Sanqushan Limestone the Sanqushan Fm. Lai et al. (1993) restudied systematically the sequence of the Sanqushan Fm, and divided it into Yaojiakeng Member, Jitoushan Member and Xiazhen Member, in ascending order. Among them, the term Yaojiakeng Member is a new name, and the other two are derived from Jitoushan Limestone of Rong et al. (1987) and Xiazhen Limestone of Chen Junyuan et al. (1976).
Synonym: (三衢山组）
Lithology and Thickness
The Sanqushan Fm is composed of a sequence of carbonate rock. Lower part is dominated by dark gray limestone. Upper part is composed of dark gray thin-bedded limestone. Top part is represented by brownish yellow calcareous sandstone intercalated with limestone. In the type area, it recorded a maximum thickness of 1534 m.
Relationships and Distribution
Lower contact
The Sanqushan Fm rests conformably on the Huangnigang Fm.
Upper contact
Regionally, it is overlain by the Wenchang Fm of latest Ordovician.
Regional extent
It is restricted to Jiangshan and Changshan of western Zhejiang, and Yushan of northeastern Jiangxi. Lai (1987) described the conodonts, and considered it to be equivalent to the Taoqupo Fm. Coeval with the Changwu Fm that is also in western Zhejiang.
GeoJSON
Fossils
The upper part yields abundant corals such as Agetolites, Palaeofavosites, Plasmoporella, Catenipora.
Age
Depositional setting
Additional Information