Introduction to the superimposed sedimentation of ancient pools: Jiutian Cave is a fine cave that exceeds the standard in terms of chemical accumulation landscape type, and its grade is the highest in the country. There are more than 200 tourist attractions in the cave, which are mainly composed of secondary chemical sediments and their various forms. Among the more than 40 common conventional chemical deposition types, Jiutiandong has 38 types and 7 rare microscopic chemical deposition types.