Chishui Fm

Eastern Fujian. The Chishui Formation was established in 1994. The section on which the formation was established is from the Chishui highway to Daiyunshan of the Dehua County, Fujian.

The Chishui Formation corresponds the C and D members of the Nanyuan Formation in the Chishui-Daiyunshan area of the Dehua County, which has now been assigned to the third formation of the Nanyuan Gr and attributed to Late Jurassic. Zhang Wentang et al (1976) and Cao Zhengrao et al (1982) attributed it to Early Cretaceous. The viewpoint that the Chishui Formation is assigned to Early Cretaceous is adopted in this lexicon.

The Chishui Formation is built up by a set of moderately acidic- acidic volcanic rock series, which is roughly divided into the upper and lower members. Lower member is represented by dark gray dacite, rhyolite-dacite tuff lava and ignimbrite with thin-bedded sandy shale. Upper member is represented by gray white and purple gray rhyolitic crystal tuff, tuff lava, rhyolite and ignimbrite with sandy shale. The formation is 2798.5 m thick.

Its upper member yields floras Cladophlibis sp., Dictyzamites sp.; and Estherias Orthestheria sp. in Nanwei of Yongtai; and floras Cladophlebis exilijormis, Otozamites sp. and Estheria Yanjiestheria sp. in Baidu of Yongtai.