THE DEPOSITIONAL SYSTEM OF FLUVIAL-CONTROLLED SHALLOW-WATER DELTA AND COAL-ACCUMULATION ANALYSIS IN WESTERN SHANDONG

The large-scale fluvial-controlled shallow-water deltaic depositional system is developed in the upper part of the Permo-Carboniferous coal measure.It is the product of rapid progradation of terrigenous elastic sediments in the period of Lata Paleozoic large scale retreat of sea water.The authors study thoroughly the genetic factes and internal architecture of the depositional system,subdivide the depositional system into two parts:the upper deltaic plain and the lower deltaic plain,the former is developed well in the study area,The study show that the fluvial-controlled shallow-water deltaic depositional system experenced two comprehensive evolution stages,from grownth to abandon. The abandon stage was the best period for coal-accumulating.And the intensity of coal-accumulation was positively related to the lasting time, the more universal the peat swamp and the thicker the coal layers.