依兰—伊通断裂带的晚第四纪构造变形与分段活动习性

发布时间：2018-06-01 14:23

  本文选题：郯庐断裂 + 依兰-伊通断裂带　； 参考：《中国地震局地质研究所》2016年博士论文

【摘要】：依兰-伊通断裂带是郯庐断裂带北段的重要组成部分,构成了我国东北地区规模最大的发震构造。不同于郯庐断裂带的潍坊-嘉山段和下辽河-莱州湾段,依兰-伊通断裂带的地震事件记录较少。自东三省有人类文字记载以来,该断裂带一直缺乏6级以上强震的历史记录。1973年有台网记录以来,该断裂带上迄今为止所记录到的最大地震发生在黑龙江省萝北县,震级为Ms5.8级。因此,普遍认为它是第四纪早期活动断裂。最新研究结果表明,依兰-伊通断裂带的舒兰盆和方正盆地存在全新世地表破裂的古地震遗迹,发生过7.0级以上强震,并且上次大震活动的离逝时间不长。这一结果改变了传统认识,同时也产生了诸多新的科学问题:(1)除了舒兰和通河2个全新世破裂段以外,是否存在其它的晚第四纪活动段?如果有,其晚第四纪以来的构造变形特征如何?(2)该断裂带的活动习性如何?是否存在分段特征?(3)该断裂带及其邻区的新构造变形特征如何?对我国东部的现今构造应力场有何启示?这些科学问题成为研究依兰-伊通断裂带及东北地区新构造与活动构造的最基础地球科学问题。因此,围绕这些科学问题,论文选取依兰-伊通断裂带作为研究对象,以活动断裂的分段研究作为主线,借助于遥感解译、野外调查、槽探与钻探、地震勘探、地震学和构造地貌等研究方法,从断裂带的不同段落在几何结构、构造地貌、活动习性和深部地球物理场的差异性等多个方面入手,综合、系统地研究依兰-伊通断裂带的晚第四纪构造变形和分段活动习性,力求科学地评价其未来强震危险性,并从区域构造角度探讨其地球动力学作用。通过本论文的研究工作,取得了如下主要成果和进展:(1)野外地质调查结果表明,该断裂晚第四纪以来活动强烈,具备强震的孕震能力和构造背景。该断裂至少发育舒兰、通河、尚志和汤原4个全新世活动段,及萝北、依兰、延寿和五常4个晚更新世活动段。这一结果从根本上改变了我们对该断裂“弱活动或不活动”的传统认识,对完善和补充东北地区的活动构造图像,及开展强震危险性分析具有重要的参考价值和指导意义。(2)通过断裂带断错地貌填图和几何结构调查认为,断裂带几何结构分段特征明显。不同段的几何图像和运动性质存在明显差异,各段规模不等,多在平面上呈左阶斜列展布,但断裂的主体已不再沿袭原来的边界断裂活动,而是迁移到盆地内部。这暗示着依兰-伊通断裂带的现今活动具有新生性,处于新生阶段的生长期或幼年期。断裂带在空间展布上具有不连续性,表现为较为明显的分段特征。各段的走向、倾向、内部及两侧地质体岩性和沉积物厚度、断裂带组合形态、断裂带宽度和分支断裂以及横向构造的发育等方面存在明显差异。断裂带各个段落沉积物厚度方面的差异比较明显,指示断裂带各段落运动性质和滑动速率方面所存在的差别;断裂带宽度的段落差异明显,段落之间存在明显的过渡区,宽度发生陡变;同时,研究发现断裂带的宽度与横向断裂的数量呈现出较为明显的正相关关系,宽度大则横向断裂数量多,宽度越小则横向断裂数量少。断裂带数量的增加多发生于界限区,对应于断裂带宽度发生显著变化的位置。综合上述几何结构差异可将该断裂分为6个主段,即沈阳-昌图段、四平-吉林段、舒兰-五常段、尚志-方正段、方正-汤原段和汤原-萝北段,长度分别为120Km、148Km、140Km、90Km、120Km和129Km,相邻主段落之间的界限区长度分别为55Km、23Km、20Km、14Km和16Km。(3)断裂带附近的地貌特征及河流水系形态分析结果表明,断裂带的构造地貌特征呈现出明显的分段特征。断裂带两侧的地形地貌起伏和断裂的几何展布存在一定的耦合关系。河谷坡降、河流弯曲度和纵剖面等地貌特征在不同段差异显著,而小尺度微观地貌的表现形式各不相同,规模不等,反映了断裂不同段的活动性存在差异。根据断裂带内部小尺度地貌的差别可将舒兰-五常段、尚志-方正段、方正-汤原段和汤原-萝北段这4个主段细分成8个亚段,即缸窑亚段、五常亚段、尚志亚段、延寿亚段、通河亚段、依兰亚段、汤原亚段和萝北亚段,长度分别为80Km、51Km、30Km、55Km、70Km、30Km、20Km和104Km。亚段界限区的长度分别为9Km、5Km、12Km和13Km,各亚段分段界限区对应着地形的突变区,和明显的地形高差起伏差异。8个新活动段形成的微地貌表现形式各不相同,陡坎、线性槽谷、小水塘和小丘陵隆起等微地貌并存;地表破裂延伸长度不一,变化幅度介于1.5Km-70Km之间;陡坎微地貌高度不等,变化从1.0m至4.4m;这些微地貌所发育的位置均位于上述主段的划分框架之内,没有突破主段的分段界限区,且较好的对应了8个亚段的划分结果。(4)通过典型点的地貌测量、年代样品测定、古地震探槽的揭露和历史地震考察,获得了该断裂晚更新世以来不同时间段的滑动速率,得到了断裂晚第四纪以来8个段落存在强震活动的证据。各新活动段除了具有相对独立的活动历史外,在晚更新世晚期和全新世晚期表现出丛集活动的特征。(5)地球物理勘探和航磁重力异常等深部探测资料表明该断裂的地表分段结果在深部有较好的对应性。断裂各段活动历史不尽相同,控制的盆地形态差异显著,断裂不同段落的强震危险性存在分段性和不均匀性。跨断裂带的地震反射剖明研究结果表明,不同段落控制的沉积盆地具有显著不同的沉积演化差异,尤其表现在控盆断裂及其结构特征等方面。断裂带的6个段落分别控制了6个盆地的结构、沉积和演化过程,差异显著。沿断裂带走向的地震震中空间分布图像、布格重力异常和航磁异常等地球物理场也存在对应的分段差异。断裂带沿走向的地震震源深度分布结果反映了不同段落地壳结构和断裂切割地壳深度的差别。综合来看,依兰-伊通断裂带存在层次分段的特征,几何结构分段、构造地貌分段、活动习性分段和深部结果具有较好的一致性,据此可将其分为6个主段和8个亚段两个不同的段落层次。主段的分段依据主要是综合分段结果,亚段的划分主要是依据微地貌和古地震的差别。但无论是亚段的规模还是亚段界限区的规模,分别都小于主段的规模,和主段落分段界限区的规模。(6)断裂带的几何结构变异(宽度陡变,走向弯曲和阶区的发育)和横向构造的发育构成了断裂带分段界限区的最主要标志。此外,断裂带宽度和断层条数的变化、地貌的陡变等在分段界限区也较为常见。界限区的几何结构多比较复杂,而各段落的几何结构则相对比较简单。绝大部分的界限区均发育有断裂几何结构的变异和横向构造,构成了分段的几何障碍体。相对于主段而言,4个亚段界限区的标志相对比较单一,主要为几何变异和横向构造的发育,但其规模均小于主段界限区。(7)依兰-伊通断裂带及其邻区新生代期间广泛发育挤压变形构造。中强地震震源机制解和野外地质调查结果表明,以松辽盆地、依兰-伊通断裂带和大安-德都断裂带为代表的东北盆地群和区域性NE向断裂现今运动性质均表现出明显的逆冲挤压特征,表明东北地区处于近EW向主应力与近SN向主张应力的现代构造应力场环境。依兰-伊通断裂带西部的松辽盆地内部广泛发育挤压反转构造。盆地内部的大安-德都断裂带平面上呈左阶雁列展布的4段,剖面上表现为宽约20-30Km的断褶变形带;地震反射剖面的综合解释结果表明,大安-德都断裂带新生代以来的构造变形表现为“断裂相关褶皱”,最新活动时代为Q2早期。如果假定其反转变形的时间为~65Ma,并假定缩短缩率固定不变,则大安-德都断裂新生代以来的缩短量约2.26Km,缩短速率约0.03mm/a。未来短时间内该断裂难以积累大于Ms7.0级地震的能量。(8)新生代构造挤压变形在东北地区可能是多阶段的过程。位于松辽盆地边缘的依兰-伊通断裂带,和盆地内部的大安-德都断裂带在新生代期间均经历了该挤压变形,形成了T02(~65Ma)、Td(~23Ma)、Ttk(~5.3Ma)和T01(~1.8Ma)4期明显的区域角度不整合界面,代表着该地区经历了至少4次强烈的幕式挤压变形。同时,该构造挤压反转可能是区域性的。三江、方正、汤原、伊通和渤海湾等东北地区一系列新生代盆地中均发生了同时期的挤压构造变形,并形成了相应的区域角度不整合界面。这指示东北地区新生代期间的区域构造应力场发生了重大改变,同时期的挤压缩短影响了整个东北地区的新构造变形,其动力学来源可能综合受控于西太平洋板块斜向俯冲和印度板块碰撞的远程效应。(9)位于松辽盆地边缘的依兰-伊通断裂带具备强震的孕育和深部背景。相反,位于松辽盆地内部的大安-德都断裂带,则只具备中强地震(M7.0)的构造背景。这暗示着松辽盆地作为独立的活动地块,其内部变形相对比较稳定,主要的构造变形和强震活动都发生在盆地的边界断裂带上。论文的研究内容和认识在一定程度上深入了我们对依兰-伊通断裂及其邻区的新构造与活动构造研究,有助于我们认识该地区的地震活动背景,能为东北地区的防震减灾工作提供一点科学参考。
[Abstract]:The Yilan Yitong fault zone is an important part of the northern part of the Tanlu fault zone, which constitutes the largest seismogenic structure in the northeast of China. Different from the Weifang Jiashan and lower Liaohe Laizhou Bay section of the Tanlu fault zone, the seismic events of the Yilan Yitong fault zone are less recorded. Since the East three provinces have human written records, the fault zone is one of the faults. Since the historical record of strong earthquakes with a direct lack of magnitude 6 or more, the largest earthquake recorded so far in the fault zone has occurred in Luobei County, Heilongjiang Province, and the magnitude is Ms5.8. Therefore, it is generally considered to be an early Quaternary active fault. The latest research results show that the Shulan basin and Fang Zhengpen of the Yilan Yitong fault zone are the latest research results. The paleo seismic remnants of the ground surface rupture in the Holocene have occurred more than 7 magnitude earthquakes, and the time of the last great earthquake is not long. This result has changed the traditional knowledge and produced many new scientific problems: (1) in addition to the 2 Holocene ruptures in Shulan and Tonghe, there are other Late Quaternary activities, such as What are the characteristics of tectonic deformation since the late Quaternary? (2) how is the activity habit of the fault zone? Is there a piecewise feature? (3) what are the new tectonic deformation characteristics of the fault zone and its adjacent areas? What is the revelation to the present tectonic stress field in the eastern part of China? These scientific questions have become a new study of the Yilan Yitong fault zone and the northeast region. In this paper, the Yilan - Yitong fault zone is selected as the research object, and the research methods of remote sensing interpretation, field investigation, channel exploration and drilling, seismic exploration, seismology and tectonic geomorphology are used as the main line of research on these scientific problems. On the basis of the geometric structure, the tectonic geomorphology, the activity habit and the difference of the deep geophysical field, the different paragraphs systematically study the late Quaternary tectonic deformation and subsection activity habits of the Yilan Yitong fault zone, and try to evaluate the danger of the strong earthquakes in the future scientifically, and discuss the geodynamics from the regional tectonic perspective. Through the research work of this paper, the main achievements and progress are obtained as follows: (1) the field geological survey shows that the fault has strong earthquake activity since the late Quaternary period, and has strong earthquake ability and structural background. The fault at least developed the 4 Holocene activities of Shulan, Tonghe, Shangzhi and Tang yuan, and Luobei, Yilan, Yanshou and Wuchang 4. This result has fundamentally changed our traditional understanding of the "weak activity or inactivity" of the fault. It has important reference value and guiding significance to perfect and supplement the active tectonic images of the northeast region and to carry out the analysis of the danger of strong earthquakes. (2) through the fault zone fault landform mapping and the geometric structure adjustment. It is found that the geometric structure of the fault zone is distinctly segmented. There are obvious differences between the geometric images and the motion properties of the different segments. The sections of each segment are different in scale and are mostly in the left order slope on the plane, but the main body of the fracture no longer follows the original boundary fault activity, but migrates to the interior of the basin. This suggests the present life of the Yilan Yitong fault zone. There is a new stage of growth or infancy in the new stage. The fault zone has discontinuity on the spatial distribution, which is characterized by more obvious segmental features. The trend and tendency of each segment, the lithology and sediment thickness of the internal and bilateral geological bodies, the combination form of the fault zone, the width of the fracture zone and the branch fracture and the development of the lateral structure. There are obvious differences in the aspects of the thickness of each section of the fault zone, which indicates the difference in the motion property and the sliding rate of each section of the fault zone, and the difference in the width of the fault zone is obvious. There is a clear transition zone between the paragraphs, and the width of the section is abrupt. At the same time, the width of the fracture zone is found and the width of the fault zone is found. The number of transverse faults is more obvious, and the width is large, the number of transverse faults is more, the smaller the width is, the number of transverse faults is less. The increase of the number of fracture zone occurs mostly in the boundary area, which is corresponding to the position of the fracture zone width. The fault can be divided into 6 main segments, that is, Shen, that is, Shen. Yang - Changtu section, Siping - Jilin section, Shulan - Wuchang section, Shangzhi Fangzheng section, fangzheng Tangyuan section and Tangyuan Luobei section, the length of the length is 120Km, 148Km, 140Km, 90Km, 120Km and 129Km. The length of the boundary zone between the adjacent main sections are the geomorphic features near the fault zone of 55Km, 23Km, 20Km, 14Km and 16Km. (3) and the form analysis of river flow system. The tectonic geomorphic features of the fault zone show obvious segmental features. There is a certain coupling relationship between the topographic and geomorphic relief on both sides of the fault zone and the geometric distribution of the fracture. The landform features of the river valley slope, the river bend and the longitudinal profile are distinct in different segments, but the small scale microlandscape forms are different in different forms and are different in scale. According to the difference of small scale geomorphology within the fault zone, the 4 main segments of Shulan Wuchang section, Shangzhi - Fangzheng section, fangzheng Tongyuan section and Tongyuan Luobei section are subdivided into 8 subsections, namely, the sub section of the jar kiln, the Wuchang subsection, the Yanshou subsection, the Yanshou subsection, the Tonghe subsection, the Yilan subsection, the Tongyuan subsection and the subsection of the fault. The length of the subsection of Luobei, the length of 80Km, 51Km, 30Km, 55Km, 70Km, 30Km, 20Km and 104Km. subsections are 9Km, 5Km, 12Km and 13Km. The subsections of the subsections correspond to the catastrophic regions of the terrain, and the difference in the elevation difference of the terrain. The micro geomorphology of the pond and the hilly uplift coexist, the length of the surface rupture extends between 1.5Km-70Km, the height of the steep ridge is different from 1.0m to 4.4m, and the location of these microgeomorphology is located within the framework of the main segment, and it does not break through the subsection boundary area of the main segment, and it corresponds well to the 8 subsections. (4) through the geomorphological survey of the typical points, the dating of the age samples, the revelation of the paleoseismic exploration trough and the historical earthquake investigation, the sliding rate of the different time periods since the late Pleistocene has been obtained, and the evidence for the existence of strong earthquakes in the 8 paragraphs of the late Quaternary fault has been obtained. At the end of the late Pleistocene and late Holocene, the characteristics of cluster activities were shown in the late Pleistocene and late Holocene. (5) deep exploration data, such as geophysical exploration and aeromagnetic gravity anomalies, showed that the subsection results of the fault had a better correspondence in the depth of the fault. The results of seismic reflection in the cross fault zone show that the sedimentary basins controlled by different sections have distinct differences in sedimentary evolution, especially in the control basin fracture and its structural characteristics. The 6 segments of the fault zone control the structure of the 6 basins, the deposits and the structures, respectively. The spatial distribution image of the earthquake epicenter along the fault zone, the geophysical field of the Bouguer gravity anomaly and the aeromagnetic anomaly also have the corresponding sectional differences. The results of the seismic source depth distribution along the strike zone reflect the difference between the crustal structure of different paragraphs and the depth of the cutting of the earth's crust. The LAN Yitong fault zone has the characteristics of hierarchical subsection. The geometric structure is segmented and the geomorphic subsection is constructed. The activity habit segmentation and the deep results have good consistency. According to this, they can be divided into 6 main segments and 8 subsections of two different paragraphs. The subsection basis of the main segment is mainly the result of the comprehensive subsection. The subdivision of the subsection is mainly based on the micro. The difference between the landform and the ancient earthquake. However, the scale of the subsection or the subsection is smaller than the size of the main section, and the scale of the subsection boundary zone in the main section. (6) the variation of the geometric structure of the fault zone (the width of the width, the development of the bending and order areas) and the development of the transverse structure constitute the most important part of the sectional zone of the fault zone. In addition, the width of the fault zone and the change of the number of faults and the abrupt change of the geomorphology are more common in the subsection boundary area. The geometric structure of the boundary area is more complex and the geometric structure of the paragraphs is relatively simple. Most of the boundaries are developed with the variation and transverse structure of the fractured geometric structure, which constitute several segments. Relative to the main segment, the marks of the 4 subsections are relatively single, mainly the development of geometric and lateral structures, but their scale is less than the main section. (7) the Yilan Yitong fault zone and its adjacent area are widely developed by extrusion deformation during the Cenozoic. The results show that the Northeast basin group and the regional NE fault zone, represented by the Songliao Basin, the Yilan Yitong fault zone and the Dan Du fault zone, show obvious thrust characteristics of the present movement characteristics of the regional NE faults, indicating that the northeast region is in the modern tectonic stress field near the EW principal stress and the near SN orientation stress. The Yilan Yitong fault zone is in the northeast area. The compressional inversion structure in the Songliao basin is widely developed in the western part of the basin. The 4 section of the Da'an dedu fault zone in the basin shows the 4 section of the left order wild wild wild wild wild wild wild wild wild wild, and the section shows a fault fold belt with a width of about 20-30Km, and the comprehensive interpretation of the seismic reflection section shows that the tectonic deformation of the Daan dedu fault zone is "fracture" since the Cenozoic. "Related folds", the latest activity era is early Q2. If it is assumed that the time of its inversion is ~65Ma, and the shortened shrinkage is fixed, the shortening of the Daan dedu fracture since the Cenozoic is about 2.26Km, and the rate of shortening for about 0.03mm/a. in the short time is difficult to accumulate more than the Ms7.0 magnitude earthquake. (8) the Cenozoic tectonic extrusion The compression deformation may be a multi-stage process in the northeast area. The Yilan Yitong fault zone, located on the edge of the Songliao Basin, and the Daan dedu fault zone inside the basin all experienced this extrusion deformation during the Cenozoic period, forming a distinct regional unconformity interface between T02 (~65Ma), Td (~23Ma), Ttk (~5.3Ma) and T01 (~1.8Ma), representing the area. At least 4 intense episodic extrusion deformation has been experienced in the region. At the same time, the tectonic compression inversion may be regional. In a series of Cenozoic basins in Northeast China, such as Sanjiang, fangzheng, Tong Yuan, Yitong and Bohai Bay, the same period of compressive tectonic deformation occurred, and the corresponding regional unconformity interface was formed. This indicates the new northeast region. The tectonic stress field of the region has changed greatly during the period of the generation, and the compression shortening of the same period affects the new tectonic deformation of the whole northeast region, and its dynamic source may be controlled by the long distance effect of the oblique subduction of the Western Pacific plate and the collision of the India plate. (9) the Yilan Yitong fault zone at the edge of the Songliao basin has strong earthquakes On the contrary, the Daan dedu fault zone, located in the inner Songliao Basin, is only with the tectonic setting of the middle strong earthquake (M7.0), which suggests that the Songliao basin is an independent active block, its internal deformation is relatively stable, and the main tectonic deformation and strong earthquake activity occur on the boundary fault zone of the basin. The research content and understanding, to a certain extent, deepened our study on the new structure and active structure of the Yilan Yitong fault and its adjacent area, which will help us to understand the background of seismic activity in this area and provide a scientific reference for the earthquake prevention and disaster reduction work in the northeast.
【学位授予单位】：中国地震局地质研究所
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P315.2
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本文编号：1964491