中扬子区晚石炭世碳酸盐岩的古岩溶成岩相

中扬子区晚石炭世碳酸盐岩与上覆早二叠世地层之间存在沉积间断／剥蚀面，并发育古风化壳．剥蚀面之下，碳酸盐岩古岩溶作用广泛发育，具有层间不平整剥蚀／溶解面、岩溶砾—角砾岩、溶解裂隙及与之连通的岩溶洞穴等古岩溶作用特征．将古岩溶作用叠加于先成碳酸盐岩地质体的一种特殊成岩环境的物质表现称为古岩溶成岩相．成岩环境可以暴露地表、近地表，成岩介质主要是大气淡水．区域碳酸盐岩古岩溶成岩相有特定的岩石学、粘土矿物、微量元素、氧碳同位素特征．垂向可以分带，横向可以对比，是一种对油气储集空间形成极为有利的特殊成岩相

The Ancient Karst Diagenetic Facies of Late Carboniferous Carbonates in the Middle Yangzi Area

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.