Xinlong Fm
Type Locality and Naming
The Xinlong Formation was erected by the Guangxi Regional Geological Survey Team in 1962. The section for the designation is in Xinlong of the Pingnan County of Guangxi.
Lithology and Thickness
The Xinlong Formation is mainly represented by a set of purple red sandy conglomerate with siltstone and shale, which is roughly divided into two parts. Lower part is mainly built up by purple red clastic rocks with sandstone and siltstone. Upper part is purple red siltstone with conglomeratic sandstone and sandy shale. It is 2390 m thick.
Relationships and Distribution
Lower contact
The base of the formation marked by purple red clastic rocks is distinguished from clayey siltstone of the underlying Daling Formation. It shows an angular discordance with the underlying Jurassic.
Upper contact
The conformable top marked by clayey siltstone is bounded by massive conglomerate of the overlying Dapo Fm.
Regional extent
The formation is distributed in the Dazhou, Ziliang and Shuiwen basins of southeast Guangxi. It is quite persistent in lithology and varies considerably in thickness. It is 2390 m thick in the Dazhou basin, 514 m in the Ziliang basin and 461 m in the Shuiwen basin. It lies unconformably on the Jurassic, the Triassic or the Paleozoic strata, and conformably or disconformably under the overlying strata.
GeoJSON
Fossils
The formation yields ostracods Cypridea sp., Limnocypridea sp., Cypridea (Morinina) ordinata, Sunliavia tumida; bivalves Trigonioides kodairai, Nakamuranaia chingshanensis, Nippononaia subrotunda, Plicatounio aff. suzukii; estheria Bairdestheria sp.; Dinosauria Asiatosaurus kwangshiensis, Prodinodon kwangshiensis.
Age
Depositional setting
It belongs to fluvial-lacustrine deposition.
Additional Information