Where is the karst landform in China? Why is it formed?

I distribution of karst landforms in China

Karst landform is also called karst landform in China. The karst landforms in China are widely distributed and have many types, which are rare in the world. In China, carbonate rocks (such as limestone, dolomite, gypsum, rock salt, etc. ) is widely distributed, which is the material basis of karst landform development. According to incomplete statistics, the total area is 2 million square kilometers, of which the exposed area of carbonate rocks is about 6.5438+0.3 million square kilometers, accounting for about 654.38+0/7 of the total area of the country; Buried carbonate rocks cover an area of about 700,000 square kilometers. Carbonate rocks are distributed in all provinces and regions of China, but Guangxi, Guizhou and eastern Yunnan are the most widely distributed. Carbonate rocks are also widely distributed in western Hunan, western Hubei, eastern Sichuan, Shandong and Shanxi.

Second, the causes

Karst landform is formed by limestone under the action of karst. Karst refers to the dissolution, erosion, transportation and sedimentation of soluble rocks dominated by carbonate rocks under the action of water and gravity. Among them, chemical corrosion and mechanical corrosion are often carried out at the same time and complement each other. Its proportion varies with karst development degree and runoff characteristics. Erosion includes erosion, abrasion and gravity erosion of carbonate rocks by water flow. The dissolution of carbonate rocks is a reversible chemical reaction. This reaction can only be carried out smoothly in natural water, because water contains acid (mainly carbonic acid). Therefore, chemical dissolution refers to the process that the soluble components of carbonate rocks are moved into water and transported in the form of ions and molecules under the action of natural water. Soluble rocks are karst, which is called karstification.

The essence of karst is the dissolution and precipitation of soluble rocks by water containing carbon dioxide.