Abstract: The physical and chemical properties and the hydrocarbon compositions of Epiproterozoic crude oils in Siberian, East European and Arabian plates are satudied. It is found that the Precambrian crude is of some special features besides natures of phanerobiotic crude, that is, it contains abundant C light isotope, and in its aliphatic composition dominates normal paralfn hydrocarbons. According to hydrocarbon biomarker composition of crude in Siberian platform, the crude can be divided into four groups, of which two groups are also found in East European and Arabian platforms. The study shows that the difference of crude properties among these platforms is relaled to the most primary prokaryole lipoid in local ecologic s8g of Precambrian ocean and the simplest eukaryote lipoid in biochemistry.

Key words: Eurasia, Cambrian, crude oil, hydrocarbon biomarker, carbon isotope