Tiankeng Landscape or Ceiling Pit Landscape

This is a unique large-scale collapse landform in karst areas in which the depressions can be wider and deeper than 100 m. The width-depth ratio is approximately 1, and most of the rock walls are vertical. Tiangkengs, or ceiling pits, usually develop in the thick vadose zone in the deep depressed areas of a peak cluster. Based on the mode of formation, they can be classified into collapse tiankeng and erosional (scouring) tiankeng, and the former is more common. The nomenclature of this landform is different in different regions of China. It is called a ‘rock bay’ in Xingwen, ‘stone courtyard’ in Wulong, ‘dragon pot’ in Yunyang, ‘stone circle’ in Leye, ‘tiankeng (heavenly ditch)’ in Fengjie and ‘tuo (heap)’in Pingtang. The term ‘tiankeng’ (heavenly ditch)’ is taken from the Xiaozhai tiankeng in Fengjie County, Chongqing City. It was first proposed as a karst tiankeng by the karstologist Zhu Xuewen in October 2001 to describe a negative landform in a calcium carbonate area with steep...