摘要
GC/MS analytical data of 60 saturated and aromatic fractions revealed that saturated hydrocarbons from Pinghu Formation coal-bearing source rocks in the Xihu Depression of the East China Sea Shelf Basin are characterized by abundant diterpenoid compounds originated from resins of coniferous trees and dominant C29 in steranes(>45%).Compared with coals and carbonaceous mudstones,dark mudstones show a relatively higher content of C27 sterane and a bimodal distribution in n-alkanes,suggesting a certain proportion of aquatic organism contributions in the organic matter source.Source rocks as a whole are believed to be deposited in an oxic limnetic-facies environment,as reflected by high Pr/Ph ratios ranging mostly from 3.5 to 8.5 and abundant dibenzofuranes.