The Analysis Of Palaeoenvironment And Paleogeographic Characteristics In Benxi Formation Of Carboniferous From Eastern Liaoning

Carboniferous is one of China's three major coal forming periods.As the first age of Carboniferous,Benxi Formation has important significance in aspects of depositional environment and coal evolution conditions for Carboniferous.With multiple sections as the research object,the paper analyzed the characteristics of paleontology,petrology and geochemistry in Benxi Formation of eastern Liaoning.In the region,main rock type is sandstone and carbonate,and the mineral composition of sandstone mainly includes quartz,feldspar and clay minerals.Clay rock is gray-white or gray-black,which mostly consists of clay minerals.Fossils pieces of animals and plants are found in some strata.Abundant fossils are found in the Formation,and plant fossils mainly include Lepidodendron,Sublepidodendron and Neuropteris etc.Animal fossils mainly include biogenic reef,brachiopoda and conodont etc.Through systematic research,speculating that the climate environment of Benxi was warm and humid at that time.In the aspect of geochemistry element contrast,making sedimentary environment analysis through sediment elements.With the specific introduction of seven element rations,responsing the change of environmental factors and summing the characteristics of environmental change in the process of mineral deposit.Condering that Niumaoling area in Benxi period has experienced the process of three sedimentary systems of clastic shore,coastal plain and mixed deposits.Finally,the paper combines with the research method of paleogeography,mapping as a member for the unit.Through the analysis and summary,to explore the coal-forming condition.