华北晚古生代层序地层模式及其演化

华北晚古生代沉积建造是在陆表海环境向大陆环境演化的背景下形成的,其层序地层模式包括陆表海型、过渡型和湖泊型等3类。陆表海型层序的底界面为IP型,顶界面为IP型和I型层序界面,层序内由海侵体系域和高位体系域构成;过渡型层序的底、顶界面均为I型层序界面,层序由陆表海低位体系域、海浸体系域及高位体系域构成,陆表海低位体系域以发育席状砂体为特征;湖泊型层序的顶、底界面亦为I型层序界面,层序由低位体系域,水进体系域和高位体系域构成。该沉积建造的形成经历了上述3种模式5个阶段的演化,这5个阶段是盆地的形成、发展、鼎盛、萎缩和转化阶段,分别对应于DS₁~DS₅这5个沉积层序。

SEQUENCE STRATIGRAPHIC MODELS AND THIRE EVOLUTION OF LATE PALAEOZOIC IN NORTH CHINA

The depositional formation of late Palaeozoic in North China was formed under the background of sedimentary environment transformed epeiric sea into continental.There are three kinds of sequencestratigraphic models, which are epeiric sea type, thransitional type and lake type-sequence.The bottomboundary of epeirie sea type-sequence is lP type sequence boundary,and the top boundary is lP or I type sequence boundary.The sequence only consisted of transgression systemtract and highstand systemtract.Bothbottom and top boundary of the transitional type sequence are I type sequence boundary.The sequence consisted of epeiric sea lowstand, transgression.and highstyand systemtract.The characteristic of epeiric sealowstand systemtract is development of flat-bedded sand-body.The boundary of lake type sequence is similarto the transitional type sequence.Its bottom and top boundary also are I type and the sequence is consisted oflowstand,water transgression,and highstand systemtract.The formation of the depositional formation undergone the above three kind models evolution.The evolution process could be divided into five phase,which arebasin formation phase,basin development phase,basin prosperity phase,basin withered phase and basin tansitional phase.The above five phases are corresponding to the five depositional sequenses from DS,To DSS.