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1.
南海西缘断裂带的地球物理特征及其构造地质意义   总被引:1,自引:0,他引:1       下载免费PDF全文
南海西缘断裂带以8°N为界分为南北两段。主断裂是一条形成于中生代的基底断裂,在新生代为持续活动的断裂带,并控制了沿断裂带及其邻近分布的新生代盆地的发育。断裂带内无磁性的高密度岩体属于印支期或燕山第1,4,5期之中的某一期花岗岩侵入体,它很可能是燕山晚期的产物。该断裂带的基底断裂在万安盆地的延伸段位于盆地中部;万安盆地东缘断裂带是新生代以来受盆地中部基底断裂右行走滑的扭张应力作用,在盆地东部边缘引发断陷而形成的。  相似文献   

2.
南海西缘断裂带以8°N为界分为南北两段.主断裂是一条形成于中生代的基底断裂,在新生代为持续活动的断裂带,并控制了沿断裂带及其邻近分布的新生代盆地的发育.断裂带内无磁性的高密度岩体属于印支期或燕山第1,4,5期之中的某一期花岗岩侵入体,它很可能是燕山晚期的产物.该断裂带的基底断裂在万安盆地的延伸段位于盆地中部;万安盆地东缘断裂带是新生代以来受盆地中部基底断裂右行走滑的扭张应力作用,在盆地东部边缘引发断陷而形成的.  相似文献   

3.
万安盆地位于南海西南部印支块体东南端即万安断裂以西地区。前人关于万安断裂活动特征及其对万安盆地形成演化的控制作用存在较多争议。通过对万安盆地区域地质背景、地质特征以及万安断裂走滑活动规律的综合分析认为,万安断裂是一条早期形成(中生代晚期)、多期活动的走滑断裂。万安断裂活动切割了盆地新生代地层,形成较多负花状构造,但该断裂仅引起盆地局部区域新生代地层产状变化,远离该走滑断裂的地层未受影响。万安盆地走滑伸展特征不甚明显,而具有明显的裂谷盆地特点,初步分析认为,万安盆地应为具有走滑性质的大陆边缘裂陷盆地。  相似文献   

4.
南海万安盆地构造沉降及其油气成藏控制作用   总被引:11,自引:0,他引:11  
万安盆地是南海重要的新生代含油气盆地之一,是较为典型的新生代走滑拉张盆地。根据对横穿盆地的多道地震反射剖面的平衡剖面模拟和断层活动速率计算,可知万安盆地经历了4个主要构造沉降过程,而断层大多为源自基底的生长断裂,在晚始新世—早中新世盆地发生走滑拉张断拗沉降阶段,断层活动最为强烈。各构造沉降阶段分别控制了盆地中油气生成、运聚和保存等成藏条件与过程。  相似文献   

5.
南沙群岛万安盆地是位于南海西南海盆被动边缘上的张性沉积盆地。通过分析区域地球物理场特征及断裂分布,以及地震剖面的解释并结合钻井资料对比分析,在万安盆地新生代沉积中对比解释出T1,T2,T3,T4,T5,T6和Tg等7个地震反射界面。其中,Tg,T5和T3为3个区域不整合面的反射波,由这3个区域不整合面将盆地新生代沉积划分为3个构造层:Tg-T5,T5-T3和T3一海底。由此推测万安盆地在新生代经历过3次构造运动,因此其构造演化史经历了3个阶段:神狐运动(白垩纪未至古新世早期),南海运动(晚始新世至早渐新世)和万安运动(中中新世末)。从神狐运动到南海运动为万安盆地的奠基期,从南海运动至万安运动则是万安盆地的发展期,万安运动之后至今日是万安盆地的形成期。万安盆地的构造发育史和珠江口盆地东部的发展史相似,故推测它藏有丰富的油气资源。  相似文献   

6.
华北板块东部新生代断裂构造特征与盆地成因   总被引:22,自引:3,他引:19  
华北板块东部新生代的构造特征及动力学演化主要受左行郯庐断裂带和右行兰考-聊城-台安-大洼-法哈牛断裂带的控制。这两条断裂都是新生代岩石圈断裂。在兰考-聊城-台安-大洼-法哈牛断裂带以西,新生代伸展盆地为NNE走向的铲形正断层控制的箕状断陷;两断裂之间为北断南超的NWW走向的断陷盆地;郯庐断裂以东的北黄海盆地为南断北超的Nww走向的断陷盆地。这些构造特征继承了该区中生代的构造格局,但其构造性质发生了根本变化,在这两条走滑方向相反的断裂带控制下,这两条断裂带内古近纪以张扭作用下的裂陷为主,随后以伸展断陷为主,第四纪沿两断裂带局部发生挤压,而鲁西地块和渤海湾盆地区仍然为伸展正断。渤海湾盆地及邻区这些新生代复杂的断块或断裂构造格局受控于应力-应变-基底格局3个基本要素。  相似文献   

7.
北康盆地构造特征及其构造区划   总被引:3,自引:0,他引:3  
北康盆地是位于南沙中部海城的新生代沉积盆地,新生代沉积盖层在盆地内广泛发育,根据地震反射特征及地震反射界面的区域对比,盆地基层可进一步划分为3个构造层。北康盆地西南边界发育延贾断裂,该断裂西起万安盆地,向东直于加里曼丹。从渐新世始,廷贾断裂先后经历了3次规模较大的构造活动。南沙海槽西北缘断裂位于北康盆地的东南边界,该断裂把北康盆地和南沙海槽盆地分隔开来。北康盆地内断裂主要有北东、北西和南北向三组,其中南北、北西向断层往往错断北东向断层。在详细讨论断层特征和沉积盖层布规律的基础上,对北康盆地的二级构造单元进行了划分。  相似文献   

8.
万安盆地是南海重要的新生代含油气盆地之一,是较为典型的新生代走滑拉张盆地。以TACross的旋回层序地层学为指导,利用钻井、地震资料、岩心等各种实际资料,建立了万安盆地新生代层序地层格架,并对万安盆地的可容纳空间变化与层序形成的主要控制因素(构造沉降、海平面升降及沉积物供应)进行了综合分析研究。  相似文献   

9.
利用SEABAT8111多波束系统在南海西南部珊瑚礁区海域进行地形地貌探测,同时还进行了单道和多道地球物理调查。探测表明该区珊瑚礁礁体的活动断裂主要有NE、NW、SN向3组。NE向断裂主要分布在岛礁区内,是晚燕山期南海第一次海底扩张时形成的断裂系,强烈活动于晚白垩世—始新世,晚第三纪以来继承性活动,以张剪性断裂为主,现今活动性中等至弱。NW向断裂主要分布在曾母盆地,以张剪性断裂为主,切割至基底,强烈活动于渐新世至上新世,构成了曾母盆地的主要张裂期,第四纪仍有活动,均为弱活动断裂。SN向断裂主要有南海西部的滨海断裂带,它是南海SN向扩张时期的转换断层,具张剪性,为中活动断裂,是南海西南部珊瑚礁区活动性较强的断裂,该断裂带历史上曾有火山活动和地震活动的记录。  相似文献   

10.
南海西缘断裂带是一条典型的右旋走滑断裂系统,是南海扩张的西部边界,两端形成具有明显走滑特征的“Y”型和“人”型构造。其前锋端形成走滑-伸展叠瓦扇,尾端形成走滑一收缩叠瓦扇,中部形成走滑一拉分双重构造的右旋走滑系统。其动力主要来源于白垩纪以来的印一藏碰撞、新生代印支挤出和南海扩张作用。经历了两期构造运动而形成的该断裂系统对其周边盆地的形成起到了主要控制作用。  相似文献   

11.
为了揭示高邮凹陷南断阶许庄—竹墩地区复杂断裂系统的成因、演化与油气成藏的关系,通过对不整合面地层剥蚀量计算、构造演化剖面分析等方法,系统地总结了许庄—竹墩地区断层的发育演化规律。吴堡运动和三垛运动时期是断裂活动最强烈的时期,许庄—竹墩地区的地层受到较强的剥蚀作用。本区主要断层的发育顺序依次为真①断层、纪③断层、真②’断层和真③断层,同一断层在不同的地质时期和平面上的不同位置,发育强度有明显的差异性。断层的活动一方面形成了一系列的断块圈闭,另一方面是油气垂向运移的主要通道,因此在本区形成了一系列的断块圈闭油藏。  相似文献   

12.
本文依据大榭岛西北海域的测深、浅地层剖面和底质土工试验资料,详细分析了该海域海底地形形态、微地貌状况、浅部地层结构及底质工程性质,发现该海域海底地层断陷构造明显,并圈定了地层断陷的范围,探讨了其形成的原因和发生的时间。  相似文献   

13.
Polygonal fault systems (PFS) are widely developed along many continental margin basins and some interior cratonic and foreland basins. They are networks of small normal faults that are usually found in tiers which are crudely layer-bound successions consisting mainly of fine-grained sediments. Their origin has been widely debated with explanations ranging from dewatering of overpressured layers to gravitational loading under fixed lateral boundary conditions. Their distribution in fine-grained intervals suggests that their genesis is connected to their initial lithology. Recent experimental work suggests that diagenesis of clay-rich sediments can lead to shear failure under low confining stresses. This explanation accords well with all subsurface observations of PFS made to date, and seems the most likely mechanism to explain their genesis. This diagenetic mode of shear fracturing in fine-grained sediments could be much more prevalent than in polygonal fault systems alone, and this has significant implications for shale gas exploration, CO2 sequestration and exploration for methane hydrates.  相似文献   

14.
The synsedimentary faults and basin-marginal fans located in the central part of the deep-water area of the early Oligocene Qiongdongnan Basin have been investigated using seismic profiles, boreholes, and well-log data.Through the formations of the characterized paleogeomorphology, such as transverse anticlines, fault ditches,and step-fault belts, the synsedimentary faults are known to have controlled the development position,distribution direction, and extension scales of the basin-marginal fans. For example, at the pitching ends of two adjacent faults, transverse anticlines developed, which controlled the development positions and distributions of the fans. During the early Oligocene, the faults controlled the subsidence center, and fault ditches were formed at the roots of the faults. In the surrounding salient or low salient areas, which were exposed as provenance areas during early Oligocene, the fault ditches acted as the source channels and determined the flow paths of the clastics, where incised valley fills were obviously developed. The fault ditches which developed in the sedimentary basins were able to capture the drainage systems and influenced the distributions of the fans. The large boundary faults and the secondary faults generated two fault terraces and formed step-fault belts. The first fault terrace caused the clastics to be unloaded. As a result, fans were formed at the entrance to the basin. Then, the second fault terrace caused the fans to move forward, with the fans developing in a larger extension scale. The results obtained in this study will potentially be beneficial in the future prospecting activities for reservoirs and coalmeasure source rocks in the basins located in the deep-water areas of the South China Sea.  相似文献   

15.
琼东南盆地中央坳陷带拆离断层及其控盆作用   总被引:4,自引:1,他引:3  
Using regional geological, newly acquired 2D and 3D seismic, drilling and well log data, especially 2D long cable seismic profiles, the structure and stratigraphy in the deep-water area of Qiongdongnan Basin are interpreted. The geometry of No.2 fault system is also re-defined, which is an important fault in the central depression belt of the deep-water area in the Qiongdongnan Basin by employing the quantitative analysis techniques of fault activity and backstripping. Furthermore, the dynamical evolution of the No.2 fault sys-tem and its controls on the central depression belt are analyzed. This study indicates that the Qiongdongnan Basin was strongly influenced by the NW-trending tensile stress field during the Late Eocene. At this time, No.2 fault system initiated and was characterized by several discontinuous fault segments, which controlled a series small NE-trending fault basins. During the Oligocene, the regional extensional stress field changed from NW-SE to SN with the oceanic spreading of South China Sea, the early small faults started to grow along their strikes, eventually connected and merged as the listric shape of the No.2 fault system as ob-served today. No.2 fault detaches along the crustal Moho surface in the deep domain of the seismic profiles as a large-scale detachment fault. A large-scale rollover anticline formed in hanging wall of the detachment fault. There are a series of small fault basins in both limbs of the rollover anticline, showing that the early small basins were involved into fold deformation of the rollover anticline. Structurally, from west to east, the central depression belt is characterized by alternatively arranged graben and half-graben. The central depression belt of the Qiongdongnan Basin lies at the extension zone of the tip of the V-shaped northwest-ern ocean sub-basin of the South China Sea, its activity period is the same as the development period of the northwestern ocean sub-basin, furthermore the emplacement and eruption of magma that originated from the mantle b  相似文献   

16.
主要讨论了南沙海槽断裂带的活动性和构造演化过程,并对海槽及附近海域的地质稳定性因素进行了分析。发现南沙海槽有活动断裂、火山岩侵入、海底滑塌和地震等不稳定因素。南沙海槽形成演化过程较为复杂,经历过多期逆冲推覆变形和褶皱隆升等构造活动,其中逆冲和隆升等活动现今可能仍在进行,属于次不稳定区域。另外,海槽西南端有滑塌现象和海底阶梯存在,工程地质条件较差。所以,海槽及邻近海区的工程建设需要特别注意这些不稳定因素,应尽量避开不稳定地区或采取工程加固措施等。  相似文献   

17.
断块油藏储量计算中夹层的识别与剔除   总被引:1,自引:0,他引:1  
岩性夹层和物性夹层在陆相沉积中非常普遍,通过岩性和物性特征识别取心井夹层,根据不同夹层的测井响应特征识别非取心井的夹层,并按照一定的标准剔除,能更加合理地确定有效厚度,精细表征油藏地质特征,取得客观的储量数据。  相似文献   

18.
位于东海XH凹陷的Y构造,以其两侧发育的NE—NNE向高角度逆冲断层和构造顶部发育的NW、近EW向的正断层、平面展布的“S”型构成其独特的构造风格。本文致力于应用T.P.Harding的扭动构造理论,结合该构造的成因机制进行了分析,并得出结论:Y构造为中新世末期的龙井运动压扭作用的产物。  相似文献   

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