【作者】 叶琳；

【导师】 任建业；

【作者基本信息】 中国地质大学 ， 能源地质工程， 2013， 博士

【摘要】 黄骅坳陷孔南地区是渤海湾盆地最早开始沉积新生代地层的区域之一,发育古近系和新近系完整的地层充填序列,具有丰富多彩的伸展、走滑和反转构造变形样式,记录了渤海湾盆地中部较为完整的新生代构造演化过程。前人曾依据早期的2D地震资料和钻井资料,对该区的沉积体系、层序地层、构造及其演化过程做过较为全面的研究,但对孔南地区的构造研究仍存在系统性和整体性不强的问题,同时对渤海湾中部兰聊走滑断裂带上走滑与伸展两大构造系统的相互关系也缺乏更深入的研究。本文以“整体、动态、综合”的盆地动力学、构造解析和构造-地层分析的研究思路和方法为指导,以丰富的地震资料、尤其是新采集的覆盖孔南地区的高精度3D大连片地震数据体为基础,综合岩心、测井数据等地质资料,结合低温热年代学研究方法,确定了孔南地区关键构造变革界面及其地质意义,确定了孔南地区新生代结构构造特征；定量分析了盆地内主要断裂系统的构造演化历史,恢复了新生代盆地古构造格架和构造演化的幕式过程,最后将研究区置于渤海湾盆地的总体框架内,从区域上总结和分析了构造-地层演化的深部地球动力学和周缘板块构造重组事件背景,讨论了孔南地区以及渤海湾盆地中部构造演化的控制机制。论文主要包括以下几个部分：第一章主要讨论了论文选题的目的与意义,总结了伸展型盆地及具有走滑性质的伸展盆地(斜向伸展盆地)国内外的研究现状、前沿和发展趋势。在对前人关于孔南地区构造研究认识阐述的基础上,针对存在的不足和问题,提出了应用沉积盆地动力学分析与模拟、构造解析及低温热年代学等新理论和新方法,通过多学科交叉,对孔南地区新生代的构造演化过程进行详细研究,并论证了本研究的可行性和重要意义。根据拟定的研究思路,确定了主要的研究内容、研究方法和技术路线。总体上,以厘清孔南地区新生代整体的构造变形格局为研究前提,结合构造解析、构造恢复和盆地动力学的方法,确定孔南地区新生代构造演化的过程,同时结合低温热年代学的方法确定和验证孔南地区重要构造演化的时间,以孔南地区为切入点,综合区域研究成果,分析渤海湾盆地中部新生代的构造演化规律,总结其构造演化的动力学背景。第二章主要从地理位置、大地构造位置、基底概况、岩石圈深部结构以及元古界-新生界充填等方面介绍了黄骅坳陷孔南地区的基本地质情况。孔南地区位于黄骅坳陷南部,盆地呈NNE向展布,由南至北呈喇叭状逐渐张开。盆地北部以沈清庄潜山-孔店潜山-羊三木扣村潜山等一系列构造凸起与歧口凹陷相隔；南部以吴桥凹陷与临清坳陷相连：东西部则分别以埕西断层、沧东断层与埕宁隆起和沧县隆起相接。孔南地区主要位于太行基底与鲁西基底的交汇部位,其地壳结构具有分层性,并且有较强烈的地幔物质上涌。自元古代以来盆地经历了四期构造运动,沉积了四套盖层,其中新生代地层在垂向上由下至上,可以划分为孔店组(Ek)、沙河街组(Es)、东营组(Ed)、馆陶组(Ng)、明化镇组(Nm)和平原组(Qp),是本次研究的重点。第三章首先通过钻井岩性、测井曲线形态变化和地震同相轴反射结构和终止方式,着重识别和追踪了黄骅坳陷新生代地层中主要的构造层序界面,其中包括具有构造变革意义的Ekl上亚段底界面——Ek1m界面。通过对高精度3D地震资料对Ek1m界面进行了闭合,并总结了该界面的识别特征。EklⅢ界面总体呈上超下削的地震反射结构特征,由于界面对下伏地层东西两端的削截作用,Ek1下亚段地层在剖面上呈现出中部厚向两侧逐渐减薄的特征；而在Ek1Ⅲ界面之上,Ek1上亚段地层沿该界面上超,并呈现标准的断陷湖盆楔状沉积地层形态,且靠近边缘断裂,楔状沉积地层内部地震反射杂乱,连续性变差。这些特征表明Ek1Ⅲ界面上下两套地层的发育具有不同的构造背景,因此,该界面具有构造变革界面的属性。在研究过程中同时也追踪闭合了孔南地区Ek3、Es3、Ng等孔南地区新生代重要构造层序界面以及C、O及Mz等前新生代的重要界面。在厘清孔南地区主要层序界面的基础上,利用古近纪底界面的起伏形态以及重要断裂的展布将孔南地区划分为3个负向构造单元分别为沧东凹陷、常庄凹陷、南皮凹陷以及4个正向构造单元,分别为孔店潜山构造带、沧市裙边鼻状构造带、小集-段六拨断裂构造带、灯明寺-乌马营断裂构造带。根据孔南地区正向构造单元结构比较复杂的特点,依据二级构造单元中构造形态及成因机制的差别将孔南地区的二级正向构造单元进行了进一步划分,孔店潜山构造带进一步划分出孔东断裂构造带、孔垒断裂构造带、孔西断裂构造带和自来屯-军马站断裂构造带四个三级构造单元；灯明寺-乌马营断裂构造带进一步划分为乌马营断裂构造带,乌马营-灯明寺断裂过渡构造带和灯明寺断裂构造带3个三级构造单元；小集-段六拨断裂构造带进一步划分为小集断裂构造带和段六拨断裂构造带2个三级构造单元；沧市裙边鼻状构造带进一步划分为舍女寺裙边鼻状构造带,店子裙边鼻状构造带和叶三拨裙边鼻状构造带3个构造单元。论文还根据盆地横纵剖面描述了不同构造单元的盆地结构样式以及构造-地层格架,并认为沧东与徐西断层的活动差异性是导致孔南地区盆地结构变化的主要因素。第四章首先对孔南地区的构造进行几何学解析,对孔南地区断裂级别、断裂的优势走向、断裂的几何形态进行了详细的描述,并对孔南地区典型的构造样式进行了分类识别,共识别出伸展构造样式、走滑构造样式、潜山构造以及火成岩构造样式。然后对孔南地区主要断裂活动进行了运动学解析,通过对孔南地区的一级、二级及部分三级断裂的古落差值统计,确定孔南地区控盆断裂的剧烈构造活动期是从Ekl上亚段时期开始的,并认为该时期剧烈活动的孔东断裂发育主要由于两侧沧东徐西断层控制两侧基底的不均匀沉降所控制。盆地内大部分三级断裂在Es3时期才开始强烈活动,并且在Esl时期这些断裂的活动性具有由盆地中部向盆地南北两侧不断增强的特点。最后运用沉降史回剥技术,结合各时期的断裂展布、残余地层分布特征,编制了孔南地区古构造格架图,将孔南地区的新生代构造演化过程分为同裂陷期和裂后期,其中同裂陷期可进一步划分为断拗幕、裂陷幕与走滑伸展幕3个幕式演化阶段。在断拗幕时期,盆地只有单一沉降中心,盆地沉积无明显的定向性,应为整体拗陷沉降的结果：裂陷幕时期盆地内孔店潜山隆起与东西两侧凹陷近平行排列的格局,显示当时盆地发育受NW-SE向伸展应力的控制；走滑伸展幕盆地内主要隆凹构造单元和断裂构造在平面上明显呈左阶斜列式展布,说明该幕时期盆地的构造运动受NNW-SSE向伸展应力控制,盆地表现出斜向伸展盆地的性质。依据典型构造演化剖面伸展率的定量计算确定盆地的伸展率在断拗幕最小,在裂陷幕显著增加,在走滑伸展幕再次减小第五章对孔南地区进行了低温热年代学方面的研究,通过磷灰石锆石裂变径迹的测试分析,认为孔南地区裂变径迹反映了盆地沉积多物源的特点,并且磷灰石裂变径迹长度分布情况表明盆地内的大多数样品都经历了复杂的构造-热事件的叠加。对磷灰石进行年龄分解后发现磷灰石裂变年龄的空间分布规律具有新老地层年龄混杂的特点,表明在Ek2与Ek1下亚段时期盆地表现为与周缘区域落差不大的坳陷湖盆,物源区的剥蚀速率不大,碎屑经过了较长时间的搬运。根据磷灰石保存径迹年龄在孔店潜山不同区域表现出来的差异性,认为新生代孔店潜山并未发生明显的隆升过程,潜山顶部保持相对稳定的状态。现今观察到孔店潜山的隆起形态实际是孔店潜山两翼基底下降使得孔店潜山表现为相对隆起的构造形态,Ek2段地层也随潜山的变形过程发生了类似的构造形态变化。将孔南地区的磷灰石裂变径迹年龄分为6组,并将6组年龄与太平洋板块及欧亚板块汇聚的重大事件进行对比分析讨论,认为孔南地区的构造演化很可能受太平洋板块运动的直接影响。第六章以孔南地区为切入点,结合周缘凹陷的盆地构造特征及构造演化分析,认为渤海湾以黄骅坳陷、临清坳陷、东濮坳陷为主体的裂陷带以及深部黄骅-德州-东明走滑构造带构成的渤海湾中部构造带在新生代的构造运动受深部走滑构造的影响非常明显,其构造演化具有整体性及规律性。在Ek-Es4沉积时期渤海湾中部构造带的沉降作用主要集中于构造带中部而两侧的黄骅坳陷中北区及东濮坳陷的构造活动较弱。在Es3-Es2时期,位于渤海湾中部构造带南北两端的黄骅坳陷中北区及东濮坳陷的构造活动显著增强,强烈的伸展裂陷使得该时期沉降中心的位置由早期构造带中部迁移至构造带南北两端。Esl-Ed时期,渤海湾中部构造带最大的两条主伸展断裂沧东断层与兰聊断裂的活动性急剧减弱,黄骅坳陷中北区的沉降中心向东迁移至歧口沿岸带以东,而东濮坳陷的沉降中心则不受兰聊断裂控制,发生了向西的迁移,主要集中在具有斜向伸展性质的长垣与黄河断裂之间的狭长地带,整个渤海湾中部构造带断裂活动性以及沉降中心的迁移表现出反向对称运动的特点。对周缘区域构造以及区域板块构造重组事件的分析表明,郯庐走滑断裂和兰聊走滑断裂的右旋走滑及其之间的拉分作用是渤海湾中部构造带新生代构造活动的主控因素。尤其是中始新世,太平洋板块向欧亚板块俯冲方向的转变促使了郯庐断裂(下辽河区段)右旋活动向南延伸和穿过渤海湾盆地中部的兰聊断裂的活化,渤海湾盆地中部构造带总体表现为斜向伸展型盆地特征,从而导致应力场向走滑断裂两端集中,使得沧东、兰聊断裂强烈活动,造成了沉降中心的迁移。渐新世太平洋对欧亚大陆向西的加速俯冲,导致郯庐断裂与兰聊断裂的右旋活动加剧,在这种区域应力条件下,渤海湾盆地中部构造带正向伸展作用大幅削弱而走滑分量影响急剧增强。本文的创新点主要体现在以下几点：1、提出孔南地区的EklⅢ界面代表了孔南地区新生代裂陷作用的起始界面,与Es3底界面一起同属于孔南地区古近纪地层序列中发育的构造变革界面。这两条界面将孔南地区古近纪同裂陷期构造演化过程分隔为断拗幕(Ek3-Ekl下亚段)、裂陷幕(Ekl上亚段)与走滑伸展幕(Es3-Ed)三幕。2、详细描述了盆地同裂陷阶段的走滑伸展幕发育的构造类型、定量计算和分析了重要断裂的活动性,编制了古构造格架图,总结了沉降中心及断裂活动性由盆地中部向南北两端的迁移规律,提出基底大型走滑断裂的右旋拉伸作用是导致该期盆地发育的主要机制。3、据磷灰石低温热年代学研究,显示潜山两翼样品都保存了新生代的构造活动信息,而潜山顶部样品仅保留有物源的信息,表明潜山顶部地层自沉积以来,其绝对空间位置并未发生明显变化,即潜山顶部在新生代的构造演化中一直保持相对稳定的状态,并未发生明显的隆升过程,现今观察到孔店潜山的隆起实际是孔店潜山两翼基底沉降使得孔店潜山表现为相对隆起的构造形态。更多还原

【Abstract】 Kongnan region in Huanghua depression is one of the areas that earliest deposited Cenozoic sediments in Bohai Bay basin. This region develops complete Palaeogene and Neogene filling sequences, and different tectonic deformation were investigated in the past decades, such as extension, strike-skip and inversion structures. These structures recorded the whole Cenozoic tectonic evolution of the central region of Bohai Bay basin. Based on the earlier released2D seismic and drilling data, previous studies provided us comprehensive understanding of sedimentary system, sequence stratigraphy, structure and their evolution. However, structure and tectonics in Kongnan region and the relationship between strike-slip and extension structures in Lanliao fault zone at central area of Bohai Bay basin should be detail studied.The whole research was guided by the theory of the basin dynamic, structure analyses and tectostratigraphy. Base on drilling, logging data and newly released high-resolution3D seismic data which cover the whole Kongnan region, we synthetically studied the Cenozoic deforming framework and evolution of the basin combined with the method of low-temperature thermochronology. Meanwhile, the quantitative analysis was used to determined tectonic evolution of the main fault systems and reconstructed the ancient structure frameworks at different geological periods of the Huanghua depression. Finally, based on the geological background of Bohai Bay basin, the evolution and deformation at the different periods were analyzed and reconstructed. And the tectonic dynamics and the deforming mechanism of the Kongnan region and central areas of Bohai Bay basin, was discussed in the background of surrounding plates and deep earth.This paper is comprised of six chapters:The first chapter mainly discussed the purposes and significance of this thesis, summarized the recent international frontier researches and futher study of extensional basin with strike-slip faulting. Based on the previous study on tectonics in Kongnan region, we utilized some new theories and methods about sedimentary basin dynamic analysis and numerical modelling, structure analysis and low-temperature thermochronology. By means of interdisciplinary study, tectonic evolution of Cenozoic stratigraphy in Kongnan region has been studied in detail. And we demonstrated the feasibility and significance of this research. According to our workflow, we present the research contents, methods and the technique in our thesis. In general,in order to reconstruct the tectonic deformation patterns of Cenozoic stratigraphy of Kongnan region, we use the method of structural analysis, tectonic reconstruction and basin dynamic. Cenozoic tectonic evolution of Kongnan region has been studied in our thesis. Then using the method of low-temperature thermochronological analysis, great tectonic framework changes occurred has been confirmed. In all, synthesizing the research results, we analyzed the tectonic evolution of Cenozoic stratigraphy in the central area of Bohai Bay basin and its dynamic background.The second chapter introduced the basic geology of Kongnan region, Huanghua depression, including geography, tectonism, basin basement, deep structure of lithosphere and Proterozoic-Cenozoic fillings. Kongnan region is located to the south of Huanghua depression, and it is a NNE trumpet-shaped trending basin. Kongnan region is in the southern of Huanghua depression. To the north of Qikou region, it is Shenqiongzhuang-kongdian-yangshanmu buried hill. To the south, it is Linqing depression and Wuqiao sag. The basin boundary faults are Chengxi fault to the east, and Cangdong fault to the west respectively.. Our study area is on the intersection of Taihang basement and Luxi basement. Its lithosphere has obvious stratification, and the mantle upwelling towad the lithosphere strongly. This basin had been experienced4stages of tectonic movements since Proterozoic, and the basin trap4suits of sediments overlying the basement. They are Ek, Es, Ed, Ng, Nm, Qp, which are our study sequence in this study.The third chapter recognized the main Cenozoic geological surfaces and tracked the main structure sequence interfaces of the Huanghua depression, based on the lithology of well logs, the changes of well log curves, and the reflection structure and their termination styles of seismic events, especially the boundary of Upper Ekl-Ek1Ⅲ which has a great tectonic significance.. Then, by studying of the high-resolution3D seismic profiles, we recognized and tracked the Upper Ekl-EklⅢ, and summarized the identification of this surface. EklⅢ Winly presents onlap or downlapon seismic profiles. As the western and eastern part of underlayer was truncated by EklⅢ, Lower Ekl presents reduction from central thick part to the sides; while, above of the EklⅢ, Upper Ekl appears as onlap to EklⅢ, and it shows a standard fault depression lack basin with wedge-shaped strata. What is more, in the wedge-shaped strata near the edge of the fault, seismic reflection was characterized by chaotic reflections and poor continuity. Those features indicate that the upper and lower strata of the EklⅢ have different structure settings. Therefore, this surface has an attibute of tectonic change. In the study, we also tracked other structural sequence boundaries such as Ek3, Es3and Ng, as well as the Pre-Cenozoic sequence boundaries such as C,O and Mz in Kongnan region..After confirmed the main sequence boundaries in Kongnan region, three negative structure units (Cangdong sag, Changzhuang sag, Nanpi sag) and four positive structural units (Kongdian buried hill tectonic belt, Cangshi nose-like structure belt, Xiaoji-Duanliubo fault structure belt and Dengmingsi-Wumaying fault structure belt) were divided. On the basis of the complicated characteristics of the positive structural units in Kongnan region, according to differences in the structure and formation mechanism of this second-class structural unit, the positive structural units were further divided. Kongdian buried hill tectonic belt was further divided into Kongdong, Konglei, Kongxi and Zilaitun-Junmazhan fault structural belts. Dengmingsi-Wumaying fault structural belt was further subdivided into Wumaying, Wumaying-Dengmingsi and Dengmingsi fault structure belt. Xiaoji-Duanliubo fault structure belt was further classified to Xiaoji and Duanliubo fault structural belts. Cangshi nose-like structure belt was further divided to Shenvsi, Dianzi and Yesanbo nose-like structure belts. In addition, this dissertation described basin structure styles and tectonic-stratigraphic basin framework of different tectonic units, and demonstrated that the main cause of the basin structural change in Kongnan region is the active difference between Cangdong and Xuxi faults.The forth chapter analyzed the structure in Kongnan region from the geometry. Then, it described levels, dominate strikes and their geometrical morphology of faults in detail., and recognized the prototype structures, those are extensional structural style, strike-slip structural style, buried hill structural style and igneous rock structural style. After that, we analyzed the activity of fault from the kinematics. According to the statistics of the original gap between each fault from three levels, we confirmed intense active stage of the basin-controlling fault started from Upper Ek1, and the growth of the Kongdong fault was caused by the differential settlement of the basements which controlled by Cangdong and Xuxi faults. Most of the third level faults activity starts from Es3, and during Esl activity stage, fault activity had been constantly enhanced from the center to north and south. Finally, by back stripping analysis technique, combing the fault distribution and its residual strata distribution of each period, paleostructure framework was reconstructed. It shows that the tectonic evolution in Cenozoic of Kongnan region could be divide into depression, rift and strike-slip stretch episodes. During depression episode, there is one subsidence center in the basin, and the deposition has no strong orient, which is a result of the whole depression subsiding. During rifting episode, parallel arrangement of the buried hill uplift and eastern-western depression shows basin was controlled by the NW-SE extensional structure. In strike-slip stretching episode, uplift-depression units and faults showed left-step oblique distribution, which means the tectonic movement was controlled by NNW-SSE extensional stress at this episode, and the whole basin represented an attribute of oblique stretch. According to the calculated of the stretching estimates from the typical structure section, basin stretching rate was minimum in depression episode, and it increased during rifting episode, while decreased in strike-slip episode.The fifth chapter discussed low temperature thermochronology analysis on Kongnan district, multi-sediment provenance of the basin was revealed by the apatite fission track analysis of Kongnan region. And apatite fission track length distribution shows that most samples within the basin experienced a complex thermal event superposition. Age decomposition of apatite showed that the spatial distribution of apatite fission has mixed old and new stratigraphic age, which indicating that the basin showed little gap with the peripheral area and was a lake depression basin in the subsegmental period of Ek2and low Ekl, the denudation rate of the source area was small and the debris were transported for a long time. This paper considered that there did not occur to a significant uplift process in Kongdian burial hill and it maintained a relatively stable state in the top of the Kongdian burial hill during Cenozoic according to the differences in different regions of Kongdian burial hill presented by apatite fission track age. The bulge morphology of Kongdian buried hill we observed today was, actually, the result of the descent of two wings of Kongdian buried hill which caused relative structural uplift, the same structural form also generated with the deformation process of buried hill in Ek2formation. We accounted that the tectonic evolution of Kongnan district was likely to be impacted by the movement of Pacific plate on the basis of dividing the apatite fission track ages into six groups and comparative analyzing them with the major syntaxes events of the Pacific plate and the Eurasian plate.The sixth chapter considered that the tectonic movement in Cenozoic of central tectonic belt of Bohai Bay which including the faulted depression whose main part are Huanghua Depression, Linqing Depression, Dongpu depression and the deep strike-slip structural belt, Huanghua-Texas-Dongming was obviously influenced by the deep strike-slip structure and the tectonic evolution has the characteristics of integrity and regularity after we took the Kongnan district as an entry point and combined with the analysis of basin structure and tectonic evolution of the peripheral depression. During the period of Ek-Es4, the precipitating actions of the middle Bohai Bay were mainly happened in the central tectonic zone whereas the tectonic activity in north-central Huanghua Depression and Dongpu depression were weak. The tectonic movement of north-central Huanghua Depression and Dongpu depression which located in the north and south ends of the central tectonic zone of Bohai Bay was significantly enhanced during the period of Es3-Es2. Strongly rifting makes the the subsidence center migrated from the middle part of structural belt to the north and south ends. During Esl-Ed period, the mobilization of the two largest main stretch faults of central structure in the Bohai Bay, Cangdong fault and Lanliao fault, were sharply weakened, the subsidence center of Northern District in Huanghua Depression eastward to the east of Qikou coastal zone while the subsidence center of Dongpu depression was not under the control of Lanliao fracture and migrated westward and mainly concentrated in the narrow strip of land between the placanticline which diagonally stretched and the Yellow River fracture. The entire central Bohai Gulf tectonic belt fracture activity as well as the migration of the subsidence center showed the reverse symmetrical movement characteristics. From the analysis of periphery regional tectonic and regional plate tectonic reorganization event we can see that the dextral strike-slip motion of Tanlu strike-slip faults and Lanliao strike-slip fault and the pull-apart motion between them were the control factors of the tectonic activity in the Central Bohai Gulf tectonic belt in Cenozoic. Especially in the Eocene, the change in the underthrust direction of the Pacific plate to the Eurasian plate prompted the dextral activities of Tanlu fracture (the Lower Liaohe section) extended to the south and the Lanliao fracture which passed the middle of the Bohai Bay Basin was activated under the drift of underthrust direction, the central structure belt of Bohai Bay constructed with the overall performance of the characteristics of oblique extensional basin, resulting in the concentration to both ends of the strike-slip fault stress field, making the Cangdong Lanliao fracture intense activity and creating the migration of the subsidence center. The acceleration subduction of Pacific westward Eurasia in Oligocene, leading the intensity of dextral activity of Tan Lu fault and Lanliao fault, the forward extensional effect of central structure belt of Bohai Bay Basin weakened dramatically but the strike-slip component affect enhanced sharply under the regional stress conditions.The innovations of this thesis are listed as follows:1. This thesis presnted Ek1Ⅲ is a Cenozoic initial rift boundary in Kongnan region. Together with Es3, these two sequences were caused by great tectonic revolution boundaries in Paleogene stratum filling. These boundaries divided syn-rift stage of tectonic evolution into depression, rift and strike-slip stretch episodes2. Structure style in rift episode has been described in detail, and we also quantitatively analyzed the activity of fault. After that, we reconstructed a tectonic framework figure during this episode, and summarized the migrated subsidence centers from center of the basin to south and north gradually. And we calculated the activity of fault at that time. What is more, we concluded that large-scale right-lateral strike-slip extension of the basement fault is the basin development mechanism in this episode.3. Apatite fission track dating shows that samples from the both wings of buried hill documented better information of the tectonic movement in Cenozoic, and samples from the top of the buried hill only tell the information of sediment provenance. It demonstrates that since sediment on the top of the buried hill, the absolute location had never been changed. That is, the top layer of the buried hill has been relatively stable since Cenozoic, and never been uplifted. We proposed that uplifting at the central of the Kongdian Buried hill resulted from subsidence of two wings of the buried hill.更多还原