A Comparative Study of Xiaonanhai Tiankeng in Nanzheng, Shaanxi Province and Dashiwei Tiankeng Group in Leye, Guangxi province

The typical karst geological relics of Dashiwei Tiankeng group in the South of China and Xiaonanhai Tiankeng group in the North of China are comparatively analyzed to helpfully deepen the understanding of the Tiankeng group in Hanzhong, Shaanxi province. Compared with Dashiwei Tiankeng group in Leye, Guangxi, from aspects of geographical background, geological conditions, geological relics and characteristics, evolution model, Xiaonanhai Tiankeng group in Nanzheng of Shaanxi is distributed in the most northern part of humid tropical-subtropical zone and developed in the karst platform area in the northern margin of the Yangtze platform. Geological relics such as Tiankeng, karst cave, shaft, cliff, canyon, peak cluster, depression, underground river, and chemical sediment, are intensively developed and combined, forming a relatively independent karst groundwater system with impervious boundary of non soluble rock series and surface watershed,showing the evolution characteristic of water-window-like endogenous sinkholes, having a high value in academic research and in landscape.