The fact that there is a strong relationship between diagenesis and matu-ration of organic matter can be believed after studying several sections inthe Liaohe Basin.The ability of clay minerals to catalyze organic reactionsinvolved in the generation of oil has been recognized.Different clay assem-blages may play different roles in the primary migration of oil from mudsource rocks.On the other hand

the presence of organic matter appears toinfluence the mechanism of smectite-illite transformation.The reaction occursin different ways when organic matter is present or not.The study of thestable carbon-and oxygen-isotope shows that organic matter is an importantcarbon source for diagenetic calcites.Organic reaction thus correlates withinorganic reaction during diagenesis

constituting a complete“geochemicalsystem of diagenesis”.