【摘要】 琼东南盆地渐新统陆源海相烃源岩是深水区的一套重要烃源岩。从盆地构造格局、古气候、沉积相和三角洲规模4个方面对琼东南盆地渐新统陆源海相烃源岩的形成机理进行了分析。结果表明：盆地构造格局整体上控制了烃源岩的发育类型，断陷期的崖城组陆源有机质主要以近岸堆积形式形成煤系烃源岩；而陵水组（E₃l）陆源有机质则以河流-三角洲搬运形式形成陆源海相烃源岩。崖城组三段（崖三段，E₃y³）和三亚组二段（三二段，N₁s²）沉积期陆源高等植物最繁盛；崖二段（E₃y²）-崖一段（E₃y¹）和陵水组二段（陵二段，E₃l²）-陵一段（E₃l¹）沉积期次之，陆源高等植物供给充足。沉积相带控制陆源有机质的差异，同时卸载的不同形成了明显差异的陆源海相烃源岩。陆源海相烃源岩有利的发育区域为三角洲前缘-内浅海以及海底扇。大规模的三角洲可以输送更高生物通量的陆源有机质，提高了烃源岩有机质丰度，从而形成海域最为重要的一类有特色的气源岩。更多还原

【Abstract】 The Oligocene terrigenous marine source rocks in the Qiongdongnan Basin serve as a significant suite of source rocks in deep-water areas.We analyze their formation mechanisms from the aspects of the basin’s tectonic framework,paleoclimate,sedimentary facies,and delta scale.The results indicate that the tectonic framework of the basin generally determines the source rock types.Specifically,the terrigenous organic matter of the Yacheng Formation,deposited during the rifting stage,predominantly accumulates offshore and forms coal-measure source rocks.In contrast,the terrigenous organic matter from the Lingshui Formation （E₃l） forms terrigenous marine source rocks via fluvial-deltaic transport.The 3^rd member of the Yacheng Formation （E₃y³） and the 2^nd member of the Sanya Formation（N₁s²） witnessed the most luxuriant terrigenous higher plants,followed by the 1^st to 2^nd members of both the Yacheng and Lingshui formations （E₃y¹ to E₃y²,and E₃l¹ to E₃l²）.These contributed significantly to an abundant supply of terrigenous higher plants.Variations in sedimentary facies zones determine the differences in terrigenous organic matter,whose differential deposition leads to the formation of significantly varying terrigenous marine source rocks.Favorable areas for the terrigenous marine source rocks include delta fronts to inner neritic zones,along with submarine fans.Large-scale deltas facilitate the transport of terrigenous organic matter with higher biotic fluxes,thus improving the organic matter abundance of source rocks.As a result,significant and characteristic gas source rocks are formed in the sea area.更多还原