Using GC/MS technique

the authors studied the dicyclic sesquiterpanes and resin acid-derived tricyclic diterpanes of the Tertiary saline-lake sedi-ments and crude oils in the Qaidam Basin.It is considered that the dicyclic sesquiterpanes may mostly come from pentacyclic triterpanes and the productsof bacteria activity;the input amount of resin derivatives was controlled by salinity of the lake water;hydrocarbon generation of resin acid took placein the early stage of thermal degradation of kerogen.So the hydrocarbon ge-nerated was enriched in low matured oil.