Gezhadi Fm
Type Locality and Naming
It was named by the Third Party of Regional Geological Survey, Sichuan Bureau of Geology in 1973 and published by the Compiling Group of Sichuan Regional Stratigraphical Scale in 1978. The type section is at Gezhadi of Niuchang, Zhongza District, Batang County, Sichuan Province.
Synonym: (格扎底组)
Lithology and Thickness
The formation, 88 m thick at the type section area, consists of unequally thick interbeds of grey to dark grey medium-bedded fine-crystalline limestone with riband marl, intercalated with knotty argillaceous limestone; the base is composed of ferriferous silty dolomitic marl.
Relationships and Distribution
Lower contact
At the type section area, the Gezhadi Fm rests on the underlying Ordovician System disconformably. Regionally, the next older unit is the Mihei Fm of earliest Silurian.
Upper contact
At the type section area, the Gezhadi Fm rests conformably overlain by the Sanze Fm.
Regional extent
The Gezhadi Fm is steady in lithology but varies in thickness, 120 m thick at Zangbala and Mulading; 150 m thick at Bomi (Bowo) and Zhizangmala, with dolomitic conglomerate at the base; mainly composed of marble in the area west of Guody, 120 m thick; completely consisting of dolomitic limestone at Wulochipu, 170 m in thickness.
GeoJSON
Fossils
It bears corals, Mesofavosites fleximurinus var. multitabulata, Cysticonophyllum batangensis, Diplochone batangensis, Favosites sp.; brachiopod Pleurodium sp., Ferganella? sp., etc., and crinoid columnal, stromatoporoid, etc.
Age
Depositional setting
Additional Information