CONTROL OF SEA-LEVEL CHANGE TO COAL ACCUMULATION IN CARBONIFEROUS-PERMIAN,NORTH CHINA

According to results of sequence stratigraphic research,the Carboniferous-Permian depositional formation in North China formed in the second order sea-level change cycle,which includes 4 cycles in the third order and 26 cycles in the fourth cycle.Several large scale coal accumulations took place in the turning period from fall to up of the third order sea-level,locating in the top of highstand system tracts.The formaion of thin coal seams correlated to the fourth order sea level change cycle and occurred in the top of parasequences.The development of coal accumulation is controlled by sea level change cycle.The sea-level change supplied potential accommodate space.The development range of coal accumulation is controlled by the period range of sea level change,which control the evolution of coal accumulation in time and space.