Guanwushan Fm
Type Locality and Naming
The type section is located at Guanwushan, northwest of the Jiangyou county seat, Sichuan Province. It was named by Zhu Sen et al. in 1942.
Lithology and Thickness
Limestone. It is mainly composed of bioclastic micritic limestone intercalated with dolomitic micritic limestone and reef limestone, and is intercalated with a few dark-gray calcareous siltstone or shale in the lower part. It is 485 m in thickness.
Relationships and Distribution
Lower contact
Disconformable contact on the paleosol at top of the underlying Jinbaoshi Fm.
Upper contact
It is conformably overlain by the Tuqiaozi Fm.
Regional extent
GeoJSON
Fossils
The formation yields very abundant benthic fossils. The brachiopods include in the lower part the upper subzone of the Jinbaoshi assemblage zone (the Stringocephalus jigonglingensis--Subresselandia guanwushanensis--Hadrorhynchus guanwushanensis subzone), and in the upper part, the Rhyssochonetes-Devonoproductus assemblage zone subdivided into a lower Uncinulus hetrocostellus-Independatrypa lemma-Gypidula laenis subzone and an upper Schizophoria excellens galeaformis-Emmanuella takuanensis subzone. The corals can be roughly divided into two successive assemblage zones of the Sinospongophyllum carinatum-Stringophyllum deples zone and the Bilingsastraea (Sichuansastraea) shawoziensis-B. (S.) beichuangensis zone. The conodonts include the Polygnathus varcus zone and the P. asymmetricus asymmetricus zone.
Age
Depositional setting
Carbonate platform (lower part is very shallow)
Additional Information