The analysis and identification of terpanes and steranes from source rocks and crude oils in the Meso-Cenozoic formations of China are made

and then various kinds of their molecular parameters have been compared.It is consi-dered that terpanes and steranes of different ages are different in components and structures.Their configurations vary with ages and maturation

so do the above mentioned parameters.It is

however

worth noting that these changes depend further on types of organic matters and degradation of crude oils by bacteria

and on the formation ages as well.