内陆表海含煤盆地Ⅲ级层序的划分原则及基本构成特点

THE CLASSIFICATION PRINCIPLE AND BASIC COMPOSITION OF GRAD-Ⅲ SEQUENCE OF EPICONTINENTAL COAL-BEARING BASIN

华北晚古生代煤系主要形成于陆内相对稳定区，古地貌上表现为受限内陆表海盆地，因此，识别层序界面及内部各级单元界面，划分层序及重建沉积体系域，需要总结出适合内陆表海盆地特点的层序划分原则和方法、技术系统。研究表明，识别沉积体系域，鉴定层序界面和各级构成单元界面，进行沉积体系和成因相的配置，划分小层序组和小层序等，这几项工作同步进行，相互映证，是内陆表海盆地层序地层分析的基本原则。

Based on the study of marginal oil and gas basin,noth American scholars put for ward a set of conceptions thought and method, forming a distinctive marginal science of sedimentology and stratigraphy──sequence stratigraphy.The classification of sequence of coal measures formed in the condition of Paleozoic epicontinental sea in North China may use the thought and methods system of sequence stratigraphy for reference but the models of the theory should not be copied mechanically. The Paleozoic coal measure in North China was formed in stable area in continent, geomorphologically show confined epicontinental basin. Therefore, it is necessary to sum up a set of sequence classifying principle, method and technique in accordance with epicontinental sea basin for the recognition of sequence boundaries and internal various order unit surfaces, for the classification of sequence and for the reconstruction of depositional system tracts. Study shows that the basic principles of sequence stratigraphical analysis in epicontinental basin is to carry out several work synchronously covering the recognition of depositional system tracts, the identification of sequence boundaries and various order composing unit surfaces, and the disposition of depositional system and genetic faces.