BIOMARKER DISTRIBUTION IN ORGANIC-MATTER OF OIL SOURCE ROCKS - IMPLICATIONS FOR LITHOGENESIS

The distribution of n-alkanes, isoprenoid hydrocarbons, metalloporphyr ins, and stable isotopes of carbon in organic matter of oil source roc ks in Russia's petroliferous regions is systematized. Analysis of the compositional variations of biomarkers in organic matter of the rocks as a function of geologic age, depth of occurrence, type of organic ma tter, and stage of catagenesis can provide a basis for using biomarker s to reconstruct the processes of hydrocarbon generation and accumulat ion. The biomarker characteristics retain their genetic significance u ntil the advanced stages of catagenesis: until MC(3)for the carbon pre ference index of n-alkanes; until MC4-5 for the pristane/phytane ratio ; until MC2-3 for the concentration of metalloporphyrins; and until MC 3-4 for the isotopic composition of total carbon of organic matter and bitumoid.