A sedimentary depositional break eriosional surface exists between the late Carboniferous carbonate and its overlying early Permial strata

and an ancient weathering crust developed in the same place. The ancient karstification of carbonate developed widely under the erosional surface. It is characterized by uneven interstrata erosion dissolution surface

karst pebble conglomerate

dissolution fissure and its connecting karst caves. The early formed carbonate superposed by ancient karstification in the special diagenetic environment is called karst diagenetic facies in the paper. The diagenetic environment may be exposed to the land surface or locate near the land surface. The diagenetic medium is mainly atmospheric fresh water. The regional ancient carbonate karst diagenetic facies is characterized by definite petrology

clay minerals

minor elements

oxygen and carbon isotopes. It can be divided into various zones in the vertical and compared in the lateral. It is a special diagenetic facies which is very advantageous to the formation of space for petroleum and natural gas.