摘要
Meso-Neoproterozoic had the most ancient and unmetamorphosed sedimentary strata,and its primary oil and gas were a notable field of energy resources.The Xiamaling Formation from Proterozoic to Paleozoic was widely distributed with relative enrichment of marine organic matter in North China.In order to understand the molecular fingerprint feature of the source rocks,GC-MS analyses were performed.Alkanes,isoprenoids,hopanes,alkylcyclohexanes,alkylmethylcyclohexanes and so on have been found in the Precambrian rocks which are 1 400-1 320Ma old.The indicators of saturated hydrocarbon showed that the depositional environment of source rocks was reductive shallow sea.The input of precursor was dominated by prokaryote organisms,and steranes were not detected.The results suggest that the Precambrian rocks with prokaryote organisms can also be good source rocks,with good prospects for primary oil and gas resources.