Abstract:

Lower Paleozoic marine sedimentary rocks in Tarim Basin are characterized by the distribution of biomarkers coming from algae and bacteria, including the distribution of lower carbon number n-alkanes with even carbon predominances or odd carbon predominances and the distribution of lower carbon number alkyl cycloalkanes with even carbon predominances. Gammacerane,,aarotanes, pristane and phytane are widespread, and the contents of rearrange steranes are lower than that of regular steranes, but the contents of tricyclic terpanes are higher. Cambrian sedimentary rocks with besin marginal facies are different from Ordovician Sedimentary rocks with open platform and half-deep water shelf facies in the distribution of biomarkers. The contont of C₂₇ sterane increases from Cambrian to Ordovician. Ordovician sedimentary rocks in Tarim Basin are different from those of shallow water shelf facies in North American in the distribution of biomarkers. The later have no pristane and phytane, containing lower carbon number n-alkanes with odd carbon predominances and lower carbon number a1kyl cycloalkanes with odd carbon predominances,and are characetrized by higher content of C₂₉ sterane, the content of rearrange steranes is equal to the content of regular steranes.