Study Of High-Resolution Sequence And Law Of Coal Accumulation On Carboniferious-Permain In Area Of Wenshang-Ningyang Of Shandong Province

By utilizing the principle and method of the high-resolution sequence stratigraphy and fully collecting core and well log information, this paper systemmaticaly analyzes genetic facies and divides the depositional system of Carboniferous-Permian coal-bearing strata in Wenshang-Ningyang coalfield. It suggests that Carboniferous-Permian can be divided into four depositional system: tidal flat depositional system, barrier-lagoon depositional system, fluvial-dominated shallow water deltaic depositional system, fluvial-lacustrine depositional system. The emphasis of this paper is to identify, contrast and divide the high-resolution sequence interface, analyze the constitution of its internal units, identify and contrast the base level cycle. There are three kinds of cycles in Carboniferous-Permian coal-bearing strata of Wenshang-Ningyang coalfield, namely short-period cycle (several), middle-period cycle (nine)and long-period cycle(four). On the basis of changes of base level cycle the law of coal accumulation in Wenshang -Ningyang coalfield can be analyzed and concluded: the forming and distribution is controlled by changes of base level and the base level superimposition of different ranks controls the law of coal accumulation; incoalation appears on the certain position of base level cycle and the consistent development of peat swamp needs the equilibrium between admissible space and sediment compensation. That is to say it's the best period of becoming coal when A/C ratio that is caused by the flux changes of sediment compensation is close to 1. Besides, it studies the factors that can control coal on the basis of studying fossil plant, paleoclimate, paleogeography and paleostructure.