Gypsum karst in China

The Peoples Republic of China has the largest gypsum resources in the world and a long history of their exploitation. The gypsum deposits range in age from Pre-Cambrian to Quaternary and their genesis includes marine, lacustrine, thermal (volcanic and metasomatic), metamorphic and secondary deposits. The gypsum is commonly associated with other soluble rocks such as carbonates and salt. These geological conditions, regional climate differences and tectonic setting strongly influence the karstification process resulting in several karst types in China. Well developed gypsum palaeokarst and some modem gypsum karst is present in the Fengfeng Formation (Ordovician) gypsum of the Shanxi and Hebei Provinces. Collapse columns filled with breccia emanate upwards from this karst and affect the overlying coalfields causing difficult and hazardous mining conditions. Gypsum karst is also recorded in the middle Cambrian strata of Guizhou Province and the Triassic strata of Guizhou and Sichuan Provinces. Gypsum-salt lake karst has developed in the Pleistocene to Recent enclosed basin deposits within the Qinghai-Xizang (Tibet) Plateau.