Samples of the Mesozoic source rock, crude oil and oil-bearing sands from Fuxian area in the southern Ordos Basin were collected systematically. Gas chromatography-mass spectrometry (GC-MS) was performed on the saturated hydrocarbon fractions extracted from these samples for discussing their biomarker characteristics and crude oil origin. The results show that on the basis of biomarker source parameter distribution, the Mesozoic source rock can be divided into five types (type A₁、A₂、A₃、A₄ and B), and the crude oil can be grouped into three types (I, II and III). Type I crude oil is derived from type A₁ source rock (Chang 7 oil shale deposited in a reducing, deep lacustrine facies environment). Type II crude oil is sourced from type A₂ source rock (Chang 7 dark mudstone deposited in subreducing to reducing, deep or semi-deep lacustrine facies environments). Type III crude oil is sourced from type A₃ source rock (Chang 7 dark mudstone deposited in a sub-reducing to reducing, semi-deep lacustrine facies environment).

southern Ordos Basin  /  Fuxian area  /  biomarker characteristics  /  oil-source correlation  /  biomarker