【作者】 金宠；

【导师】 李三忠；

【作者基本信息】 中国海洋大学 ， 海洋地质， 2007， 硕士

【摘要】 渤海湾盆地区中生界是近年来中国东部深部油气勘探的主要目标,但其中生界构造演化与样式始终不明朗。黄骅坳陷和济阳坳陷不仅是渤海湾盆地区中生界潜山油气的重要勘探区,而且处于渤海湾盆地中新生代构造格局转换部位,具有重要研究价值。同时,中生代该区处于整个华北克拉通东部高原的核心部位。其构造演化研究对深入理解中国东部岩石圈减薄和这个高原的形成至垮塌的过程至关重要。本文利用大量地震剖面,采用平衡剖面技术,系统进行了中生界残存展布规律的分析,探讨了该区中生界构造特征、演化过程、动力学背景及盆地原型。系统理顺渤海湾盆地中生代时空关系和构造特征,得出:1.印支期,在南北向挤压力下黄骅坳陷和济阳坳陷均以发育EW-NEE向宽缓褶皱为主,三叠系残存于向斜处并受左行走滑影响,为挤压挠曲盆地。燕山早期在NWW-SEE挤压力下,NE走向逆冲和褶皱发育,中下侏罗统残存于呈NE-NEE向展布的右行走滑影响的后陆挤压挠曲盆地内。2.通过兰考-聊城-沈阳断裂两侧中生界构造对比,燕山中期,右行压扭兰考—聊城—沈阳断裂开始作为一整体NE向的断裂系开始控制渤海湾盆地区,沧东断裂右行压扭,同时NNE左行压扭郯庐断裂活动逐渐增强。黄骅坳陷和济阳坳陷构造发生差异。晚侏罗世,黄骅坳陷南区右行压扭走滑拉分,黄骅中北区右行压扭走滑挠曲,上侏罗统残存于拉分盆地内和挠曲向斜处;济阳坳陷地块发生逃逸构造,NW向断层反转为正断层,上白垩统残存于逃逸拉分盆地内。早白垩世是渤海湾盆地区构造转换的关键时期,黄骅坳陷和济阳坳陷几乎所有方向断层均发生负反转运动,地壳抬升至最高,黄骅坳陷南区处于高原中心,不残留白垩系;黄骅坳陷中北区下白垩统盆地原型为张扭性质裂陷盆地;济阳坳陷逃逸作用继续。逃逸拉分作用亦继续。3.从各残留构造层地层展布规律得出中国中生代高原又从NWW向SEE迁移的规律,早白垩世,黄骅坳陷位于此高原的核心部位,尤其是黄骅坳陷南区。通过黄骅坳陷中生界构造特征和济阳坳陷中生界构造特征的对比,联系逃逸构造和前人的研究资料推得中国东部岩石圈减薄及下地壳拆沉应在早白垩世之前,减薄最大时期在早白垩世,因而导致中国东部高原开始垮塌于燕山中期。而燕山晚期,无论黄骅坳陷和济阳坳陷,处于高地势部位,且在燕山V幕微弱的褶皱和逆冲断层构造作用下,基本不残存上白垩统。更多还原

【Abstract】 Mesozoic strata of Bohai bay basin are an important and new oil-gas exploration objective to search for Mesozoic buried hill, but their Mesozoic structural pattern and evolution are not clear yet. The Huanghua and Jiyang depressions are important and new oil-gas exploration areas, and are also mark a change of Mesozoic–Cenozoic structural patterns in the Bohai Bay basin. Moreover, these two areas were sited at the center of a Mesozoic plateau in north-eastern China craton during the Mesozoic. Their structural evolution is a key problem to understand lithospheric thinning in eastern China and the formation and subsequent collapse of this plateau. Therefore, the study area has important implication for future research. A large number of seismic profiles were interpreted to analyze the distribution of relic Mesozoic strata. Combining them with balanced sections, we discuss their Mesozoic structural evolution,dynamic mechanism and original basin characteristics. Finally we got the following conclusion:1.During the Indosinian period,Huanghua and Jiyang depressions developed gentle EW-NEE folds and thrust belts under NS compression. Triassic sediments are found the syncline and were seriously influenced by a sinistral strike-slip. The original basin is a compressed flexural basin. Later, during early Yanshannian period, the NWW-SEE compression developed NE thrust belts and folds, middle to lower Jurassic sediments are found in a compressed flexural basin highly influenced by dextral slipping.2. The Lankao-Liaocheng-Shenyang fault is a set of NE inverse-slip faults system and controls the structure of Bohai bay basin during the middle Yanshannian, as deduced from the contrast of relic strata from both the sides of the fault. Meanwhile, Cangdong fault was dextral slipped, and the sinistral slip NEE Tan-Lu fault strengthened gradually. All of these resulted in the structure of Huanghua depression and Jiyang depression took on different aspect. During the Late Jurassic, the upper Jurassic sediments accumulated in a compressional pull-apart basin and in a flexural syncline, respectively at southern range and middle-northern range of Huanghua depression; the two basins were all seriously influenced by compression and dextral slipping. In the same time, Jiyang depression developed escape tectonic, the NW inverse faults changed into normal faults, the upper Jurassic accumulated in escape-apart basin. In the Bohai bay basin, early Cretaceous is the key period of change in tectonism; almost all inverse faults changed into normal faults. During the upper crustal uplift, Huanghua depression was located at the center of this Mesozoic plateau; lower Cretaceous only accumulated in a dextral slip faulted rift basin at the middle of Huanghua depression. The escape tectonic continued in the latter Yanshannian period in the Jiyang depression.3. We deduced that the Mesozoic plateau in north-eastern China craton changed from NWW to SEE tectonism. The Huanghua depression was located at the center of this Mesozoic plateau in the early Cretaceous. Furthermore, based on the structural contrast of Huanghua and Jiyang depression, and from previous results, we put forward the hypothesis that maximum lithospheric thinning and delamination in eastern China happened before early Cretaceous. So, the Mesozoic plateau probably collapsed in early Cretaceous. Due to Yanshannian fifth episode of folding and thrusting, there were no upper Cretaceous sediments during late Yanshannian period.更多还原