Study Of Law Of Coal Accumulation And Main Geologic Congtrolling Factorsin On Carboniferious-permain In Shandong Province

Based on collecting and arranging data of drilling and core and logging curve, Carbonic-Permian coal-bearing formations were combined systematically in genesis and sedimentary system were divided with theory of sedimentation, coalfield geology and tectonic geology. The research showed that Carbonic-Permian formations could be divided into four sedimentary systems: tidal flat depositional system, barrier-lagoon depositional system, fluvial-dominated shallow water deltaic depositional system and fluvial-lacustrine depositional system.Besides, changes of sea level of Late Paleozoic coal-accumulating basin was researched. The evolution of the basin, as well as transgression and regression of Benxi Formation, Taiyuan Formation, Shanxi Formation and upper and lower Shihezi formation were mainly studied. A major transgression occurred in earlier period of Early Permian; then large-scale regression started in Taiyuan Duration, and to Shanxi Duration the sea had regressed to the south of North China Basin ,with the areas, which was effected by sea-level changes, having been reduced greatly.Comparison of the north and south part in this area indicated that the lower Taiyuan formation is the main coal bed unit in Taiyuan formation and in which steady recoverable coal seam is developed all over the West Shandong. The general trend is that thick in the north and thin in south and condition of coal formation is better in north. Tidal-flat depositional system is the most important constituent in upper Taiyuan formation, with unsteady coal bed that 1-2 beds developed in top. The thickness of the coal bed is generally lower than 0.5m and just partially recoverable. Fluvial-dominated shallow water deltaic depositional system is developed in high stand system tract of upper Taiyuan formation and mid-bottom Shangxi formation, and is the top of land-sea interaction coal-bearing strata. The upper side is essential for filling the coal basin on the point of coal-accumulation; it contains super-thick and widespread main coal-bed.Stable land-sea interaction between coal-bearing and carbonate deposit was developed in carboniferous in west of Shandong.It was not received deposits in carboniferous east of Tanlu fault. Stable inland basin sand-mud deposit was developed in Permian in west of Shandong. It was not received deposits in Permian east of Tanlu fault.In addition,based on the research of fossil plants,paleoclimate,paleogeography and paleo tectonic, A study of coal-controlling factors in Shandong was obtained . Late Paleozoic coal in North China Plate was a product of tropical rain forests weather. Tectonic movement shaped northern China coal basin,controlled sediments and coal gathered in Permo Carboniferous, formed a marine, transition phase, continental deposition system, becamed the main coal period of Shandong and northern China.