Gelong Fm

Named by Ye Shida and Yang Tongshi in 1982. The named section is located in Yushu County, Qinghai, Jielong Benpulong-Gelong; the reference section is located in Batang Sangchi Akau, Yushu County. In 1982, Ye Shida and Yang Tongshi divided the Middle Triassic of Yushu Jialong into the lower Gelong Gr (now Gelong Fm) and the upper Benpulong Gr (now Benpulong Fm).

Synonym: Gelong Gr

It is mainly clastic rock, and can be divided into three members from bottom to top: Lower member is gray-purple-gray-green medium-thick laminated medium-fine grained feldspar-quartz altered sandstone, light metamorphic siltstone interbedded with impure biogenic mesoscopic tuff and a few claystones, 776 m thick. Middle member is gray calcareous siltstone interbedded with medium-thick impure tuff, 463 m thick. The upper member is gray medium-grained feldspar-quartz sandstone, tuffaceous slate, calcareous slate interbedded with crystalline tuff and a few volcanic rocks. It is 957 m thick.

A section producing bivalves Neoschizodus laevigatus, Neoschizodus laevigatus indetermediaeformis, Entolium disecites, Unionites sp., Daonella sp.; a section producing Ammonoids Balatonites sp., Longobarditoides sp., Cuccoceras sp., Acrochordiceras sp., Hollandites sp.; Bivalves Unionites cf. gregareus, Eumorphotis sp., Posidonia sp., Palaeonucula sp.; triturated Ammonoids Paraceratites sp.; bivalves Halobia sp., etc.

This group is marine sediment, distributed in the Yushu area in southern Qinghai, and is more fully exposed in the area of Jielong and Batang.