渤海湾盆地与苏北-南黄海盆地构造特征和成因对比

Comparison of the Bohai Bay Basin and Subei-South Yellow Sea Basin in the Structural Characteristics and Forming Mechanism

渤海湾盆地和苏北-南黄海盆地为我国重要的含油气盆地,但由于所处的构造背景不同,导致石油地质条件相差很大,对比两者在构造特征和形成演化上的异同对于探讨两盆地的油气成藏条件具有重要意义。通过实际资料并分析大量研究成果认为:两盆地均为陆相断陷盆地,内部凹陷受生长断层控制而呈"箕状",在断裂特征、活动性等很多方面具有相似性,而在盆地结构、断裂展布等方面差异明显;盆地浅部构造的形成是深部物质活动的响应,深部热隆升对渤海湾盆地形成起到重要作用但不是引起苏北-南黄海盆地裂陷的原因,扬子板块与华北板块的碰撞对两盆地基底形成起到了决定作用,滨太平洋构造域板块多次转向、俯冲是两盆地裂陷和内部构造形成的重要原因之一,印度板块与欧亚板块碰撞导致大量深部物质向东、东南逃逸而影响两盆地的演化过程。结合盆地形成的影响因素,在区域动力学分析基础上,分六个阶段解释渤海湾盆地和苏北-南黄海盆地的形成演化。

The Bohai Bay Basin and the Subei-South Yellow Sea Basin are important petroliferous basins in China and often compared with each other. Although there are many similarities between these two basins, the differences in aspects such as the abundance of the resources, the scale of the oil and gas field and the hydrocarbon evolution degree are significant. The primary cause of these differences is the different regional tectonic background. Based on the geological and geophysical data, we make a comparison of the two basins in several aspects, such as the basin architecture, internal structure, fault activity characteristics, and explore the influence factors and mechanism of the basin formation. We suggest that four main factors controlled the formation of the two basins：（1） The collision between the Yangtze and North China Plate, which happened during the Indosinian, provided the evolution foundation of the Subei-North Yellow Sea Basin. The Bohai Bay Basin evolution history may start earlier than the Subei-North Yellow Sea Basin, at Late Paleozoic. （2） The subduction of the plates in the Marginal Pacific Tectonic Domain beneath the Eurasian Plate had a significant impact on the formation of the two basins. （3） Deep earth thermal activity played an important role in forming of the Bohai Bay Basin, while that was not the reason for the Subei-South Yellow Sea Basin rift. （4） The collision between the Indian Plate and Eurasian Plate caused continuous mass injection over the past ～50 Ma, led to the diffuse asthenospheric upwelling and rifting of the two basins. Combined with the influence factors and the tectonic background, we set up the evolution models of the two basins.