Xinbagou Fm

The type section is located at Xinbagou, 2.5 km east of Waluo, Yanbian County, southern Sichuan (near Yunnan). It was named by Tong Zhengxiang et al. in 1990.

Limestone. A suite of carbonate rock formations. The Lower part is dominated by gray to gray-white thick-bedded to massive sparite bioclastic limestones, followed by crinoid micritic bioclastic limestone; 82.5 m thick. The Middle part consists of gray to gray-white thick-bedded to massive bioclastic micrite and micrite; 162.57 m thick. The Upper part is of gray and gray-white sparite bioclastic limestones, bioclastic pelleted limestone and micritic calcirudite; 100.03 m thick.

Lower part yields abundant Brachiopods Phricodothyris asiatica, Neochonetes carboniferous, Marginifera pulcher, etc.; Conodonts Declinognathodus lateralis and Idiognathoides sinuata; Corals Fomitchevella orientalis longiseptata and Paracarruthersella abnormis. Middle part contains Fusulinids Profusulinella wangyui, Pseudostaffella jomdaensis and Schubertella gracilis znensis; Corals Petalaxis sp., Paracarruthersella simplex, Arctophyllum intermedium, Amygdalophylloides gracilis and Fomichevella orientalis; Conodonts Idiognathoides sinuatus and Streptognathodus parvus; Brachiopod Reticularia novosemelica. Upper part contains abundant Fusulinids Fusulinella biconica, F. pseudobocki, Fusulina sp. and Pseudostaffella sphaeroidea; Brachiopods Choristites gigans and Buxtonia giganta; Conodonts Idiognathodus delicatus and I. humerus.

It is interpreted as a carbonate platform undergoing deepening and then shallowing. The Lower part of the formation has abundant grains, containing bioclasts and is of strong hydrodynamics, belonging platform margin shallow shoal deposits; the Middle part is an open sea platform, where the water body is still, belonging to the low-energy deposits; the Upper part contains various grainstones, where water flows unimpeded, and the brachiopod shells have been dynamically transported.