The material source of the Carboniferous karst type bauxite in North China mainly came from the underlying Late cambrian-middle Ordovician carbonate rock.
华北石炭纪岩溶型铝土矿的主要物质来源为下伏的晚寒武世—中奥陶世碳酸盐岩。
2
Taian city belongs to north limestone area, and is a place taking karst ground water as source of water supply mainly.
泰安地处北方石灰岩地区，是一个以岩溶地下水为主要供水水源的城市。
3
Liujiang basin is an important water source area of Qinhuangdao city. The surface collapse will happen at hidden karst areas, due to much exploiting of ground-water.