The Study Of Permain Sporopollen Fossil Assemblages And Their Paleoclimatic Significance Of Yichuan,Shanxi

This paper based on the project about analysis of the Yan 223 well of the Yanchang oil field.Through the study of the Paleozoic pollen assemblages,as well as the restoration of ancient vegetation,to explore the Late Paleozoic plants fossil of pollen assemblages and the significance of paleoclimate.lt has important theoretical significance and practical value.The main results and understanding of this paper are as follows:1.Yan 223 were collected the pollen samples of 30,then through the processed found 8 samples that had the pollen fossils.A total of 27 genera and 37 species(including undetermined species)were found through the detailed analysis and identification.The part of important molecules were described in detail that have greatly enriched the content of pollen fossils of the Permain.2.According to the longitudinal distribution and vertieal variation the main genus and species of pollen fossil,it can be divided into 3 assemblages as following:they are Gulisporites cochlearius-Laevigatosporites minimus,Sinulatisporites-Florinites and Lueckeisporites permianus-Platysaccus radialis.The structure and composition characteristics of these assemblages were analyzed in detail.3.According to the analysis of these pollen assemblages characteristics and by the extensive compare them with adjacent area and North China,exploring the meaning of the times of these pollen assemblages.The result shows that the overall appearance of these three assemblages are roughly the same with the Upper Paleozoic Shanxi Formation,Lower Shihezi Formation and theUpper Shihezi Formation in the Ningwu Shanxi,Tengtian Shandong and other areas in North China.Three assemblages ofthe era generally were P12-P21(?),P22(?)and P23-P3(?).4.Through the established pollen assemblages speculate the ancient vegetation types of the corresponding period,and compare with the established plant fosills by the predecessors in the same geological period,studying about the rise of the various geological periods of vegetation,development,and thriving,andrecession extinction historical process,then comparing pollen fossils with the macro-vegetation,we would have a more intuitive understanding of the ancient vegetation in the face of the Late Paleozoic.The results show that the Permian flora of the study area is typical of China flora,reflecting a warm and humidtropical rain forest climate,Late Permian with the increase in the proportion of conifers,climate began more drought.