The Physical Context of Karst in China

The distribution of carbonate rocks on the earth’s surface is uneven and irregular. Large areas of the world, like much of the shield of Africa have little or no carbonate deposits, but in China, carbonate rocks outcrop widely at the surface or exit at shallow depths below the surface, covering 1.3 million km2 or one-seventh of the country’s territory. About one-quarter of the world’s total of terrestrial carbonate rocks occurs in China. China is an immense country; its area is almost 9.6 million km2 and it comprises about 6.5% of the world’s total land area. About 10% of China’s rural population live in the karstified tropics of South China; 61% of the food supplies and 93% of the rice are produced there (Barbary et al. 1991). The major karst areas in China are located in densely populated and economically important regions, particularly in the northeast, south and southwest (Figs. 1 and 2). Moreover, the distribution of karstic rocks is so widespread that almost every geomorphological type of karst can be found in China (Ren Mei et al. 1982). If covered and buried karsts are included, in addition to surface karst, up to one-third of the country is involved. The management and development of the karst areas thus form important sectors of the economy. Almost one-quarter of the total water resources of China is of karstic origin (Yuan Daoxian et al. 1991), and a good proportion of the Chinese petroleum reserves occurs in karstic rocks. Limestones and karst in China thus permeate almost every aspect of its physical geography and no other country of comparable size (Russia, Brazil, USA or Australia for example) is so dominated in its modern geology and geography by karstic problems.