CHARACTERISTICS OF HIGH-RESOLUTION SEQUENCES OF COAL-BEARING STRATA IN EPICONTINENTAL BASIN

The features of T-R cycles in coal measures of epicontinental basin,southwestern shandong coal field is analyzed and the division of high solution sequences is presented.They are,in descending order,tectonic sequence,supersequence,sequence,parasequence sets,parasequence and lower order sequence unit.Based on sea-level changes in epicontinental basin and their control on coal formation,the view of coal formation caused by transgressive events is also presented.The study indicated that the transgressive events are important factors which control the coal formation.The episodic transgressive event surfaces,exposure pedogenese surfaces and the coal seams caused by transgressive events are of isochronic significance in the strata correlation.