【作者】 朱晓青；

【导师】 吕洪波；

【作者基本信息】 中国石油大学 ， 构造地质学， 2009， 硕士

【摘要】 渤海湾盆地经历了中新生代燕山、喜山期的强烈构造运动,构造格局错综复杂,前人对其成因解释亦是众说纷纭。本论文以地幔柱学说为指导,以济阳坳陷及其周缘小盆地为主要研究区,通过运用盆地分析与构造沉积分析方法,利用地震剖面资料分析、古应力与古流向分析、物理模拟分析、大地构造背景研究等手段,建立了渤海湾盆地的地幔柱演化模型。通过研究获得如下认识:从侏罗纪开始,渤海湾地区就开始存在地幔柱活动。进入晚白垩世,地幔柱活动开始控制盆地的构造演化。盆地演化可以划分为三个阶段:晚侏罗世到古新世的热隆起阶段、孔店组沉积期开始到沙河街组二段沉积结束的热伸展阶段、沙河街组一段沉积期开始的热沉降阶段(馆陶组沉积期结束后明显减弱)。三阶段对应不同的构造特征,并出现各具特色的沉积响应。热隆起阶段:以发育高角度张裂断层控制的地堑为特征,裂谷肩部开始产生并向外旋转,缓坡区发育的侏罗纪准同裂谷期沉积地层与白垩纪同裂谷期沉积地层在剖面上显示为两个相对的楔形。热伸展阶段:强烈拉张,裂谷肩发生大幅度旋转,裂谷肩部开始遭受剥蚀,成为盆地大面积沉积地层的物源区。盆地边缘隆起区指向盆地内部广泛发育拆离断层,从而限制了盆地区未能拉张出洋壳。热沉降阶段:该阶段盆地区伸展率明显减小,表层反转的出现标志着热沉降的开始,破裂不整合的出现则标志着热沉降的明显减弱。更多还原

【Abstract】 Bohai Bay Basin has experienced strong Yanshan, Himalayan tectonic movement, resulting in the complex tectonic framework. The previous researchers have maintained different views on its formation. In this thesis, the mantle plume model is used to build the evolution framework of the Bohai Bay Basin, taking the Jiyang Depression and its cousins in the vicinity area as the examples. The author has studied the evolution history via basin analysis, tectonic-sedimentation analysis, seismic reflection profile, the fossil stress analysis, paleocurrent direction, clastic composition and tectonic setting and physical simulation etc.The mantle plume originated in Bohai Bay in the Jurassic, and started to control the evolution of the Bohai Bay basin in the Late Cretaceous. The processes can be divided into three phases: the thermal uplift （Late Jurassic～Paleocene）, thermal stretch or thermal extension （Paleocene Ek～Es₂） and thermal subsidence （Es₁～Ng）. The three phases correspond to different structural characteristics and sediment responses.Thermal uplift phase is characterized by the grabens controlled by high angle tension faults, and the rift shoulders initiated and rotated outward. The sub-synrift sedimentary beds formed in Jurassic and the beds formed in Cretaceous show two opposite wedges in the seismic reflection profile. During thermal extension, the intense extension occurred; the rift shoulders rotated in a wide margin and started to be suffered the erosion, becoming the main source areas. The basin uplift pointed to internal basin and developed widely detachment faults, having limited the ocean crust spreading. In thermal subsidence, the basin extension obviously decreased, accompanied by the surfacial tectonic inversion showing the beginning of post-rift thermal subsidence. The thermal subsidence was obviously weakened by the end of Dongying Formation （Ed）, showing a the breakup unconformity between Dongying Formation and Guantao Formation （Ng/Ed）.更多还原