Some Features of Porphyrins and Other Biomarkers in Crude Oil and Source Rock From Continental Salt-Lake Sediments in China

Porphyrins and other biomarkers in crude oils and source rocks from several basins, especially the Jianghan Salt-lake Basin in China, are discussed. It is concluded that the main types of free porphyrin from continental sediments are similar to those from marine sediments, except that only nickel porphyrins exist in the contentinental sediments. A large amount of gammacerane is a characteristic feature of the continental salt-lake sediments of Jianghan. In addition, it is suggested that tricyclic terpane/total terpane (%), C₂₇ + C₂₈/gammacerane, gammacerane/17 α(H) hopane ratios, and changes in nickel porphyrin content can be considered as indicators of maturity.