Original Environment of Eogene Petroleum Source Rocks in the Pearl River Mouth Basin
JIANG De xin YANG Hui qiu (Lanzhou Institute of Geology, Chinese Academy of Sciences, Lanzhou 730000)
Forty seven species of fossil spores and pollen referred to 25 genera extracted from the crude oil samples collected from the reservoirs within the Upper Oligocene Zhuhai Formation in the Pearl River Mouth Basin of the North Continental Shelf of South China Sea were recorded in this paper. Based on the investigations of the spores and pollen in crude oil and their stratigraphical distribution, the Eogene petroleum source rocks of the petroliferous basin were determined. In accordance with the paleoecological characteristics of the original plants producing the spores and pollen, the sedimentary environment of the Eogene petroleum source rocks was discussed. The results of the study indicate that the black and dark grey clayrocks of the Middle Eocene Wenchang Formation and the Upper Eocene to Middle Oligocene Enping Formation should be the petroleum source rocks of the Pearl River Mouth Basin; and the petroleum source rocks might have originated and evolved in the subtropic lacustrine sedimentary environment under warm and wet climatic conditions.