南海陆缘盆地构造演化与烃源岩特征

受近南北向扩张机制控制，南海陆缘盆地或凹陷多呈NE向带状展布，总体上具有“南三北三”平行排列、外窄内宽的特点。新生代发生的4次重要区域构造运动具有穿时性，共发育3期盆地破裂不整合面，分别是早渐新世与晚渐新世之间、古近纪与新近纪之间、中中新世与晚中新世之间;由东往西，盆地破裂不整合面的时代逐渐变新。受构造运动与海平面升降影响，南海海域发育湖相、海陆过渡相和陆源海相3类烃源岩。由南北两侧向中央海盆，烃源岩类型由湖相逐渐过渡到海陆过渡相与陆源海相；从东向西，盆地主力烃源岩层位逐渐变新，由始新统-渐新统逐渐过渡到渐新统-中新统。南海海域烃源岩的分布规律与盆地破裂不整面存在密切关系:破裂不整合面形成早（早渐新世与晚渐新世之间）的盆地，主力烃源岩形成早（始新统湖相烃源岩）；反之，破裂不整合面形成晚（中中新世与晚中新世之间）的盆地，则烃源岩形成晚（渐新统-中新统海陆过渡相到陆源海相烃源岩）。

Tectonic Evolution of Epicontinental Basins in South China Sea and Their Feature of Source Rocks

Controlled by the expansion mechanism with nearly north-south direction，basins or depressions in South China Sea are mostly NE-SW extending, with three in the north and the other three in the south. The depressions parallel each other, and the ones in the center are wider than the ones around the margins.There are three basin types(pull-apart type, strike-slip type and extrusion type) that are divided into ten sub-types; In Cenozoic, there are four important regional tectonic movements that are diachroneity certainly, and develop three disrupt unconformities(between Early Oligocene and Late Oligocene, between Paleocene and Neogene, between Middle Miocene and Late Miocene), the era of disrupt unconformity is new gradually from east to west. Effected by the tectonic movement and sea-level change, the South China Sea develops three types of source rocks that are the lacustrine facies, the transitional facies and the terrigenous marine facies. From the north and south sides to the central basin, the source rock type gradually transit from the lacustrine and transitional facies to the terrigenous marine facies. From east to west, the layer of main source rock is gradually new(from Eocene and Oligocene to Oligocene and Miocene). The source rocks distribution is closely related to the disrupt unconformities, the earlier of the disrupt unconformity(between Early Oligocene and Late Oligocene),the main resource rocks form earlier(Eocene lacustrine facies source rocks) in basin. Otherwise, the later of the disrupt unconformity(between Middle Miocene and Late Miocene),the main resource rocks form later(Oligocene and Miocene transitional facies and terrigenous marine facies source rocks) in basin.