GEOCHEMICAL CHARACTERISTICS OF THE UPPER PALEOZOIC SOURCE ROCKS IN THE SOUTHERN NORTH CHINA

In the Southern North China region,a series of the Late Paleozoic formation with platform facies,transitional facies and inland lake facies had been deposited.The Upper Paleozoic source rocks mostly represent a set of successive coal-bearing squence.Combined with study of the Upper Paleozoic sedimentary settings and sedimentary facies,by using analyzed and tested geochemical data,the geochemical characteristics of organic matter abundance,type and thermal evolution of source rocks in coal-bearing strata was studied.The results confirmed that the main Upper Paleozoic source rocks were contained in the coal measure mudstone and coal-bearing rock in Taiyuan Formation and Shanxi Formation.Besides that,the condition of secondary oil generation and main controlling factors(the potentiality and temperatures) of the Upper Paleozoic source rocks was considered and it was proved that the better source rocks showed greater potential,lower initial maturity and higher geothermal gradient.In the end,it was pointed out that the secondary oil generating areas were mainly in Depressions of Tanzhuang-Shenqiu,Niqiuji,Luyi,Xiangcheng.