Pingzhang Fm
Type Locality and Naming
The type section is located at Pingzhang Village, Yingpan Township, Fengqing County, Yunnan. It was named by the Yunnan Party of Regional Geological Survey in 1981.
Lithology and Thickness
Volcanics and Limestone. A suite of mélange accumulation composed of intermediate-basic eruptive rocks, carbonaceous rock and siliceous rock. Lithologically divided into two members. Lower Member consists of marine intermediate-basic eruptive rocks (basalt and andesite), intercalated occasionally with limestone lenses in the upper part. In the type section, it is formed by 5 eruption cycles, in which the 4th and 5th cycles are intercalated with minor siliceous rock and tuff. The Lower Member is 320 m thick, and shows a general trend of thickening from north to south. Upper Member is formed by marble, dolomitic limestone and limestone, intercalated with siliceous rock and basalt, 0−105 m thick, with a general trend of thinning to pinching out southward.
Relationships and Distribution
Lower contact
Disconformable contact with the underlying Lower Devonian Series
Upper contact
Conformable contact with the overlying Shidongsi Fm
Regional extent
Distributed at Hexi of Changning east of Changningke Street, Pingzhang of Dachezi of Fengqing, Banka-Yutangzhai of Yongde, Cangyuan of Genma, etc.
GeoJSON
Fossils
Lower Member contains Corals Kueichouphyllum and Syringopora, and Brachiopod Linoproductus. Upper Member contains Corals Lithostrotion and Diphyphyllum, brachiopods Dictyoclostus and Echinoconchus, Conodonts Gnathodus, Adetognathus sp., etc.
Age
Depositional setting
It is interpreted as intermediate-basic eruptive rocks into marine setting
Additional Information