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以北部湾盆地区域构造分析为基础,在福山凹陷构造活动性研究的基础上探讨了福山凹陷形成的动力学机制,分析了凹陷东部地区古近系地层中双层结构的形成机制问题.研究认为:福山凹陷在平面上受红河断裂的左行走滑和海南隆起顺时针旋转的双重作用,流三段沉积期凹陷在旋转-拉分作用下发生强烈的水平伸展,为东部地区下构造层中的反向断层提供动力源,海南隆起的快速隆升作用形成了上构造层中的重力滑动生长断层,渐新统早期在流二段泥岩中发育的火成岩侵入体在凹陷的东部地区形成一道天然屏障,最终形成双层结构.结果表明,双层结构形成过程可划分为裂陷雏形期、下构造层伸展断裂期、中部塑性层发育期、上构造层形成期以及双层结构定形期5个主要阶段.
Based on the tectonic analysis of the Beibu Gulf Basin, the dynamic mechanism of the formation of the Fu-Shan depression was discussed based on the study of the tectonic activities in the Fu-Shan Sag, and the formation mechanism of the double-layer structure in the Paleogene strata in the eastern part of the depression was analyzed. : The Fushan sag has the dual role of left-lateral strike slip of the Honghe fault and clockwise rotation of Hainan uplift in the plane. The sedimentary sags of the third member of the Fukang Sag experienced a strong horizontal extension under the rotation-pull-off action, Reverse fault to provide power source, the rapid uplift of Hainan uplift formed the gravity sliding growth fault in the upper structural layer, and the igneous intrusions developed in the early Oligocene in the second flow mudstone formed a natural barrier in the eastern part of the depression , Finally forming a double-layer structure.The results show that the formation process of double-layer structure can be divided into the rupture phase, the extension fracture period of the lower tectonic layer, the middle plastic layer, the formation period of the upper tectonic layer and the five main phases of the double-layer structure stage.