The relationship between the organic matters and source rocks geochemistry characteristics of Middle Permian series in Yili Basin

AimTo make sure that the Midlle Permian series source rocks are important, in which the sedimentary environments were the important factors for distribution of the organic metters in Yili Basin, Northwest China.The relationship between the environment and source rocks geochemistry characteristics are probed more impotantly.MethodsCombining the analysis of geochemical data about the source rocks on outcrop sections with bore specimen, the sedimentary environments about the source rocks are studied by abundance of the organic metters in the source rocks as well as saturated hydrocarbon chromatogram parameters.ResultsThe studies show that the Midlle Permian series source rocks are distributed mainly in Tamqisayi formations and the palaeosalinity was higher and the deposional environments were weak reducing to reducing. It is considered as that the zones deposited in half deep lake-deep lake where the organic matters could been buried and preserved contemporarily in strong reducing environment, there are more abundance and better types of organic metters in the source rocks such as black grey mudsource. The zones deposited in the river-delta there are less abundance and the worse types in the source rocks like green grey mudstone. ConclusionAmong the source rocks, there are least abundance and the worst types in the carbonate source rocks that deposited under the more oxide condition, in which terrienous clastic deposits were inadequate during longer time and the palaeclimate was drier relatively. The more reducing and favorable sedimentary zones are the better place,there are higher abundance of organic metters in the source rocks with strong reducing environment,where the organic matters can be buried and preserved contemporaryly, and the source rocks are generally high in organic content, or vice versa.