Stratigraphic sequence divided and coal accumulation law of late Paleozoic coal measures in Weibei Area

In order to explore the coal accumulation law of the late Paleozoic Carboniferous- Permian coal measures in Weibei Area, a high resolution sequence str atigraphy method was applied to the high resolution sequence stratigraphy divided on the Carboniferous- Permian coal measures in Weibei Area. Taiyuan Formation an d Shanxi Formation strata were divided into 15 short- term base- level cycles and 4 medium- term base- level cycles. Based on the medium- term base- level cycles as t he comparison unit, a sequence stratigraphic framework was established. The paper discussed the locations of No.3, No. 5 and No. 11 seams in the base- level cycles and the relationship to the thickness and continuity. The results showed that the favorable coal accumulation condition had no relation to the direction of the accommod ation space variation in the process of the base- level cycles and would respond to the specific ratio between the accommodation space variation rate and the slime yiel d rate. When the specific ratio was higher than 1, the favorable coal accumulation conditions would be occurred at the rising early stage, in dropping down process and late stage of the base level. When the specific ratio was lower than 1, the favorable coal accumulation conditions would be occurred at the rising late period or the down ing early period and medium period of the base level.