成岩地层学与层序地层学

SEQUENCE STRATIGRAPHY AND SEA LEVEL CHANGES ON EARLY PALEOZOIC PALEOCONTINENTS AND THEIR MARGINS IN CHINA

层序地层学研究是通过对露头、测井和地震反射剖面研究进行的，是属宏观研究．但大量实践证明，在不少层序界面，宏观上是难于辨别的．这就有碍于正确划分层序，开展层序地层学的研究工作．任何一个层序都经历过成岩作用的改造，因此成岩地层学与层序地层学有密切的关系，特别是与表生成岩作用有非常密切的关系，在许多不整合面上形成区域性的成岩标志，如溶蚀作用、硅化作用、白云岩化作用、土壤化作用、交代作用等标志．因此，可以通过成岩作用的微观研究来识别那些隐伏的层序界面．

This paper summeries the major characteristics of megasequences, mesosequences and corresponding sea level changes on Early Paleozoic paleocontinents and their margins in China. Two megasequences (MG-1—MG-2) and five mesosequences (MS-1—MS-5) can be recognized in three paleolandmasses incuding North China, South China and Tarim. MG-1, which based on a megaunconformity and covered by a drowning unconformity, consists of MS-1—MS-3 formed from Cambrian to Early Ordovician dated 94～112Ma and is dominated by carbonate rocks containing abundant oil, gas and other minerals. While MG-2 consists of MS-4—MS-5 formed from Middle Ordovician to Silurian dated 58～68Ma and belongs to a carbonate-siliclastic depositional assemblage.