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 sequence stratigraphic models, which are epeiric sea type, thransitional type and lake type-sequence.The bottom boundary 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.Both bottom 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 sea lowstand systemtract is development of flat-bedded sand-body.The boundary of lake type sequence is similar to the transitional type sequence.Its bottom and top boundary also are I type and the sequence is consisted of lowstand,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 are basin 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 DS₁ to DS₅.