Longwangshan Fm
Type Locality and Naming
Subei Basin. The Longwangshan Formation was erected by Gu Xiongfei in 1955. The section for the designation is in Longwangshan of the Lujia Village about 16 km northeast of the Dangtu County, Anhui.
Lithology and Thickness
The Longwangshan Formation is built up by intermediate and intermediate slightly alkaline lava and pyroclastic rocks, locally slightly basic, which is divided into two parts. Lower part is built up by gray, grayish white and purple gray sediment volcanic breccia, andesitic volcanic breccia, agglomerate breccia, tuff and tuffaceous siltstone. Upper part is gray and grayish green basalt trachyandesite, hornblende trachyte, volcanic breccia with purple red tuffaceous siltstone and tuffaceous conglomerate. It is 430.15 m thick.
Relationships and Distribution
Lower contact
The base marked by andesitic breccia lava lies unconformably on the underlying Zhongshan Fm.
Upper contact
The top marked by hornblende andesite is distinguished from the overlying Dawangshan Fm consisting of andesitic volcanic breccia and shows a disconformable contact with the latter.
Regional extent
The formation mainly occurs in Ningwu, Lishui, to the east of Jurong and Maoshan. In the western part of Lushan to the east of Lishui County, the lower part of the formation is built up by gray, grayish green and purple gray andesitic volcanic breccia and hornblende andesitic breccia tuff, while the upper part gray and purple gray andesitic agglomerate breccia, sediment tuff and augite andesite. The base of the formation lies unconformably on the underlying Beixiangshan Fm while the top shows an eruptive unconformity with the overlying Dawangshan Fm. It is 724.65 m thick. In the Liyang area, the lower part of the formation is composed of purple gray augite and breccia tuff lava. In Yangjiafen of Nanjing and Guanyinshan of the Jiangning County, it lies unconformably on the Xihengshan Fm.
GeoJSON
Fossils
None listed
Age
Depositional setting
It is of volcanic facies.
Additional Information