Author: Jiang De-xin and Yang Hui-qiu
J Integr Plant Biol 1983, 25 (2): -.
Twenty-eight species (or forms) of fossil pollen and spores referred to 20 genera extracted from the crude oil samples collected from the Kuche Seg of the Talimu Basin in Xinjiang are observed. The conception of the petroleum sporopouen assemblage is further expounded and the classification of the petroleum sporo-pollen assemblage is also tentatively proposed. According to the characteristics of the assemblages, the problem on oil source of the mentioned oil-bearing region is discussed in this paper. The petroleum sporo-pollen assemblage of Jurassic reservoir of Kucbe Seg is composed of Deltoidospora perpusilla, D. gradata, Cyathidites minor, Hymenophyllumsporites deltoidus, Cingulatisporites problematicus, Cibotiumspora paradoxa, Osmundacidites ap., Cycadopites typicus, C. nitidus, Podocarpidites multesimus, Alisporites grandis, Alisporites bilateralis, Parvisaccites sp., Abietineaepollenites microalatus, A. minimus, PinuspoRenites sp., Piceaepollenites sp., etc. These species of spores and pollen have been found from the Jurassic deposits in this region or in the adjacent regions. The petroleum sporo-pollen assemblage only contains the spores and pollen which coincide with those of the reservoir in age. There is not any spore or pollen older or younger than the reservoir. Consequently, it may be referred to a monotonous type of petroleum sporo-pollen assemblage. The petroleum sporo-pollen assemblage of Cretaceous reservoir of this region consists of Deltoidospora perpusilla, Cryathidites minor, Cibotiumspora paradoxa, Schizaeoisporites zizyphinus, Osmundacidites sp., Crcadopites typicus, C. nitidus, Parvisaccites sp., Cedripites cretaceus, Abietineaepollenites microalatus, A. minimus, Pinuspollenites sp., etc. All these species distribute either in the Jurassic deposits or in the Cretaceous deposits in this region or in the adjacent regions. The distribution of Schizaeoisporites zizyphinus and Cedripites cretaceus is usually limited to the Cretaceous deposits. Both the Cretaceous species and the Jurassic species are comprised in the assemblage, so it may be referred to a composite type of petroleum sporo-pollen assemblage. The petroleum sporo-pollen assemblage of Tertiary reservoir comprises Deltoidospora perpusilla, Cyathidites minor, Cibotiumspora paradoxa, Schizaeoisporites zizyphinus, Poly-podiaceaesporites sp., Cycadopites nitidus, Podocarpidites multesimus, Parvisaccites sp., Abietineaepollenites mininus, Pinuspollenites labdacus, Piceaepollenites alatus, Cedripites ovatus, Ephedripites fusiformis, Quercoidites microhenrici, Chenopodipollis multiporatus, C. microporatus, Artemisiaepollenites sdlularis, etc. Besides the Tertiary pollen and spores, the assemblage contains the Jurassic species and the Cretaceous species, and therefore it belongs to a composite type of petroleum sporo-pollen assemblage. The monotonous type of petroleum sporo-pollen assemblage reflects that the oil source rock is coincident with the reservoir rock in age, and the composite type of petroleum sporopollen assemblage shows that the oil source rock is generally older than the reservoir rock. Based on the investigation of the petroleum sporo-pollen assemblages, the oil source rock of the Kuche Seg is considered to be Jurassic Period in age, and the Lower Jurassic Yangxia Formation and the Middle Jurassic Kuzilenuer Formation are considered to be favorable source rock. The conclusion is supported by the result of the organic geochemical investigation.