Abstract:One hundred and thirty-five species of fossil spores and pollen referred to 66 genera which were extracted from the crude oil samples collected from the North Tarim petroliferous region of the Tarim Basin were identified. Based on the investigations of the characteristics of the petroleum sporo-pollen assemblages, the geological ages and formations of the petroleum source rocks of the petroliferous region were determined. Some aspects concerning the avenues, directions, mutes, periodic sequences of oil and gas migration were also discussed. The results of this study confirm that the following Formations, viz. the Middle Triassic Karamay Formation, the Upper Triassic Huangshanjie and Taliqike Formations, the Lower Jurassic Ahe and Yangxia Formations, and the Middle Jurassic Kezilenuer and Qiakemake Formations should be the important petroleum
source rock series of the North Tarim petroliferous region.