六盘山东麓断裂带晚第四纪活动性研究
发布时间：2019-05-15 18:10
【摘要】：六盘山东麓断裂带是南北构造带北段重要的组成部分,地质构造格局和现今GPS速度剖面与龙门山构造带有很大相似性;汶川地震的发生,提示我们不能忽略断裂带两侧速度梯度弱变化的断裂,更不能因此而低估这类断裂的地震危险性。因此,对六盘山东麓断裂带的活动性深入研究,可为区域地震危险性研究与分析提供基础资料与依据。本论文主要工作有:(1)建立六盘山区域层状地貌面的时空序列;(2)寻找断层最新活动证据,求取断层活动性参数;(3)构建构造差异隆升速率(?UT)模型,引进地貌学参数河道陡峭指数(),间接分析区域隆升活动性;(4)借助已有区域精密水准数据资料和跨断层长水准测量数据,结合跨断裂带不同区段地质剖面,分析六盘山构造带垂向运动特征。通过以上多种方法或参数,综合分析了六盘山东麓断裂带晚第四纪以来活动性和构造变形特征,并且,探讨了断裂带附近这种弱速度梯度变化的现象。主要得到以下结论:(1)海原断裂带与六盘山东麓断裂带以两条左阶斜列式过渡的小断层衔接,分别为曹河村断层(f1)和包家堡断层(f2),其活动性质均以左旋水平滑动为主,可能继承了海原断裂带尾端的活动习性。(2)六盘山东麓断裂带全长约90km,整体走向近南北。断层性质主要以逆冲作用为主兼有左旋走滑。通过遥感解译、数字高程模型分析、野外地质调查将六盘山东麓断裂带划分为3段:六盘山东麓断裂带北段(F1)走向近320°-330°,为左旋走滑兼高角度逆冲性质;中段(F2)断裂走向350°-SN,为高角度逆冲性质;南段(F3)走向330°-340°,基岩中发育低角度逆冲断层,第四系沉积层中为高角度逆冲性质。(3)六盘山东麓断裂带南段(F2)晚更新世以来垂直滑动速率约0.55mm/a;六盘山东麓断裂带北段(F1)晚更新世以来水平滑动速率约为0.92-1.16mm/a,全新世以来垂直滑动速率约为0.31-0.41mm/a。(4)收集统计前人对六盘山东西两侧兰州黄河、陇西渭河及泾河地区阶地研究成果,借用古地磁及14C等方法测定阶地形成年龄和实测阶地拔河高度已有数据,引进构造差异隆升速率(?UT)参数来反映区域构造隆升强弱。通过对兰州黄河阶地、陇西渭河阶地与泾河阶地的构造差异隆升速率对比研究表明,第四系以来,兰州黄河阶地与泾河阶地4个期次平均构造差异隆升速率(?UT?????)分别为76.87 mm/ka、42.88 mm/ka、421.06 mm/ka和1050mm/ka;平均值为397.70mm/ka;陇西渭河阶地与泾河阶地3个期次内?UT?????分别为177.37 mm/ka、171.83 mm/ka和168.27mm/ka;平均值为172.49mm/ka。说明六盘山西侧总体活动性要强于六盘山东侧;同时六盘山构造带北段较南段活动性强,并有逐渐增强趋势。(5)利用均衡河道纵剖面模型,提取了六盘山地区河道陡峭指数(ksn),结合数理统计方法对数据进行对比分析。结果表明,六盘山北段、中段和南段河道陡峭指数均值分别为65.11、73.53和71.76,表现出北段较小,中、南段较大的特征。并确定河道陡峭指数的变化主要受到区域岩石隆升速率差异的影响,而研究区内岩石地层、降雨量及河流负载等地质、气候背景相关因素对河道陡峭指数的影响较小。各研究区河道陡峭指数的变化反应了六盘山南北不同区域构造隆升速率的分布特征:六盘山北段隆升速率较低,区域活动性较弱;中段区域隆升最快,活动性较强;南段区域隆升介于两者之间。(6)基于调查、分析得到六盘山东麓断裂带的活动性参数、构造差异隆升速率(?UT)、地貌学参数()、区域精密水准观察结果和水准速度剖面及不同区段地质剖面多种参数和资料综合分析认为:六盘山西侧隆升活动性强于东侧,六盘山东麓断裂带中北段构造变形及活动性呈现较强态势。说明,现今GPS速度剖面所显示六盘山东麓断裂带附近弱速度梯度但有明显应力积累的现象,可能是存在明显的应力转换。区域水平运动方式转换为以区域隆升为主的垂向运动,并且,断裂带不同区段及六盘山东西两侧有着不同的垂向运动强度。
[Abstract]:The eastern foot fault zone of the Liupanshan Mountain is an important part of the northern section of the north-south structure. The geological structure pattern and the current GPS velocity profile are very similar to the Longmen Mountain structure. The occurrence of the Wenchuan earthquake indicates that we can not ignore the weak changes of the velocity gradient on both sides of the fault zone. It is not possible to underestimate the seismic risk of such a fracture. Therefore, the research on the activity of the fault zone in the eastern foot of the Liupanshan Mountain can provide the basic data and the basis for the research and analysis of the regional seismic risk. The main work of this thesis is: (1) to establish the time-space sequence of the layered geomorphic surface of the Liupanshan region; (2) to find the latest active evidence of the fault, to obtain the fault activity parameter; and (3) to construct the construction difference uplift rate (? UT) model, introducing the geomorphology parameter channel steep index (), indirectly analyzing the regional uplift activity; (4) combining with the existing regional precision leveling data and the cross-fault long leveling data, and combining the geological profile of different sections of the cross-fault zone, The vertical movement characteristics of the six-plate mountain structure are analyzed. Based on the above methods or parameters, the characteristics of the activity and tectonic deformation since the late Quaternary of the eastern foot fault zone of the Liupa Mountain are comprehensively analyzed, and the phenomenon of the change of the weak velocity gradient in the vicinity of the fault zone is discussed. The following conclusions are obtained: (1) The Haiyuan fault zone and the eastern foot fault zone of the Liupanshan Mountain are connected with the small faults of the two left-order oblique faults, which are the fault (f1) and the Bao-jiabao fault (f2), and the active properties of the fault (f1) and the Baojiabao fault (f2) are mainly the left-hand horizontal sliding, The activity habits of the tail end of the Haiyuan fault zone may be inherited. (2) The total length of the eastern foot fault zone of the Liupanshan Mountain is about 90km, and the whole direction is near the north and south. The fault property mainly consists of the thrust and the left-handed sliding. By means of remote sensing interpretation, digital elevation model analysis and field geological survey, the eastern foot fault zone of the Liupanshan Mountain is divided into three sections: the north section (F1) of the eastern foot fault zone of the Liupanshan Mountain is in the direction of 320 掳 -330 掳, and is a left-hand sliding and high-angle thrust property; the middle section (F2) is broken to 350 掳-SN, It is a high-angle thrust property; the south section (F3) moves to 330-340 掳, and the low-angle thrust fault is developed in the bedrock, and the high-angle thrust property is in the Quaternary sedimentary layer. (3) The vertical sliding rate is about 0.55mm/ a since the late Pleistocene in the south section (F2) of the eastern foot fault zone of the Liupanshan Mountain; the horizontal sliding rate of the north section (F1) of the eastern foot fault zone of the Liupanshan fault zone is about 0.92-1.16 mm/ a since the late Pleistocene, and the vertical sliding rate since the Holocene is about 0.31-0.41 mm/ a. (4) Collect the research results of the terrace of the Yellow River, the Longxi River and the Terrace in the two sides of Liupanshan, and use the methods of paleomagnetism and 14C to measure the existing data of the terrace formation age and the measured terrace drawing height, and introduce the construction difference uplift rate (? UT) parameters to reflect the uplift of the area. The comparative study on the uplift rate of the structure difference between the terrace of the Yellow River and the terrace of the Yellow River in Lanzhou and the terrace of the Qihe River shows that, since the quaternary system, the difference of the average tectonic difference between the terrace of the Yellow River and the terrace in Lanzhou and the terrace of the river is increased (? UT--? ) The average value is 76.87 mm/ ka, 42.88 mm/ ka, 421.06 mm/ ka and 1050 mm/ ka. The average value is 397.70 mm/ ka, and the Longxi River terrace and the river terrace are within 3 stages. UT--? 177.37 mm/ ka, 171.83 mm/ ka and 1727 mm/ ka, respectively; the average value is 172.49mm/ ka. It is indicated that the overall activity of the west of Liupanshan Mountain is stronger than that of the east of Liupanshan Mountain, while the north section of the Liupanshan tectonic belt is more active than the south section, and there is a gradual increase of the trend. (5) Using the balanced channel longitudinal section model, the steep index (ksn) of the river course in Liupanshan area is extracted, and the data is compared and analyzed by means of the mathematical statistics method. The results show that the mean value of the steep indexes of the north section, middle section and south section of Liupanshan Mountain is 65.11, 73.53 and 71.76, respectively. The change of the steep index of the channel is mainly affected by the difference of the uplift rate of the regional rock, and the influence of the related factors such as the rock formation, the rainfall and the river load in the study area on the steep index of the channel is small. The change of the steep index of the channel in each study area reflects the distribution of the uplift rate in different regions in the north and south of Liupanshan. The uplift rate of the north section of the Liupanshan Mountain is lower, the activity of the region is weak, the middle section is the fastest and the activity is strong, and the regional uplift of the south section is between the two. (6) Based on the investigation and analysis, the activity parameters of the eastern foot fault zone of the Liupanshan Mountain are analyzed, and the difference of uplift rate is constructed (? The comprehensive analysis of various parameters and data of the profile of UT, the geomorphology parameter (), the observation of the regional precision level and the profile of the level velocity and the geological profile of different sections is as follows: the uplift activity on the west side of the Liupanshan Mountain is stronger than that of the east side, The structural deformation and activity of the north section in the east-foot fault zone of the Liupanshan Mountain show a strong tendency. It is shown that the current GPS velocity profile shows the phenomenon of weak velocity gradient near the eastern foot fault zone of the six-plate mountain, but there is obvious stress accumulation, which may be the obvious stress transformation. The horizontal movement of the region is converted into the vertical motion dominated by the regional uplift, and the different sections of the fault zone and the two sides of the six-plate mountain have different vertical movement intensity.
【学位授予单位】：中国地震局地震预测研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P315.2
本文编号：2477696
[Abstract]:The eastern foot fault zone of the Liupanshan Mountain is an important part of the northern section of the north-south structure. The geological structure pattern and the current GPS velocity profile are very similar to the Longmen Mountain structure. The occurrence of the Wenchuan earthquake indicates that we can not ignore the weak changes of the velocity gradient on both sides of the fault zone. It is not possible to underestimate the seismic risk of such a fracture. Therefore, the research on the activity of the fault zone in the eastern foot of the Liupanshan Mountain can provide the basic data and the basis for the research and analysis of the regional seismic risk. The main work of this thesis is: (1) to establish the time-space sequence of the layered geomorphic surface of the Liupanshan region; (2) to find the latest active evidence of the fault, to obtain the fault activity parameter; and (3) to construct the construction difference uplift rate (? UT) model, introducing the geomorphology parameter channel steep index (), indirectly analyzing the regional uplift activity; (4) combining with the existing regional precision leveling data and the cross-fault long leveling data, and combining the geological profile of different sections of the cross-fault zone, The vertical movement characteristics of the six-plate mountain structure are analyzed. Based on the above methods or parameters, the characteristics of the activity and tectonic deformation since the late Quaternary of the eastern foot fault zone of the Liupa Mountain are comprehensively analyzed, and the phenomenon of the change of the weak velocity gradient in the vicinity of the fault zone is discussed. The following conclusions are obtained: (1) The Haiyuan fault zone and the eastern foot fault zone of the Liupanshan Mountain are connected with the small faults of the two left-order oblique faults, which are the fault (f1) and the Bao-jiabao fault (f2), and the active properties of the fault (f1) and the Baojiabao fault (f2) are mainly the left-hand horizontal sliding, The activity habits of the tail end of the Haiyuan fault zone may be inherited. (2) The total length of the eastern foot fault zone of the Liupanshan Mountain is about 90km, and the whole direction is near the north and south. The fault property mainly consists of the thrust and the left-handed sliding. By means of remote sensing interpretation, digital elevation model analysis and field geological survey, the eastern foot fault zone of the Liupanshan Mountain is divided into three sections: the north section (F1) of the eastern foot fault zone of the Liupanshan Mountain is in the direction of 320 掳 -330 掳, and is a left-hand sliding and high-angle thrust property; the middle section (F2) is broken to 350 掳-SN, It is a high-angle thrust property; the south section (F3) moves to 330-340 掳, and the low-angle thrust fault is developed in the bedrock, and the high-angle thrust property is in the Quaternary sedimentary layer. (3) The vertical sliding rate is about 0.55mm/ a since the late Pleistocene in the south section (F2) of the eastern foot fault zone of the Liupanshan Mountain; the horizontal sliding rate of the north section (F1) of the eastern foot fault zone of the Liupanshan fault zone is about 0.92-1.16 mm/ a since the late Pleistocene, and the vertical sliding rate since the Holocene is about 0.31-0.41 mm/ a. (4) Collect the research results of the terrace of the Yellow River, the Longxi River and the Terrace in the two sides of Liupanshan, and use the methods of paleomagnetism and 14C to measure the existing data of the terrace formation age and the measured terrace drawing height, and introduce the construction difference uplift rate (? UT) parameters to reflect the uplift of the area. The comparative study on the uplift rate of the structure difference between the terrace of the Yellow River and the terrace of the Yellow River in Lanzhou and the terrace of the Qihe River shows that, since the quaternary system, the difference of the average tectonic difference between the terrace of the Yellow River and the terrace in Lanzhou and the terrace of the river is increased (? UT--? ) The average value is 76.87 mm/ ka, 42.88 mm/ ka, 421.06 mm/ ka and 1050 mm/ ka. The average value is 397.70 mm/ ka, and the Longxi River terrace and the river terrace are within 3 stages. UT--? 177.37 mm/ ka, 171.83 mm/ ka and 1727 mm/ ka, respectively; the average value is 172.49mm/ ka. It is indicated that the overall activity of the west of Liupanshan Mountain is stronger than that of the east of Liupanshan Mountain, while the north section of the Liupanshan tectonic belt is more active than the south section, and there is a gradual increase of the trend. (5) Using the balanced channel longitudinal section model, the steep index (ksn) of the river course in Liupanshan area is extracted, and the data is compared and analyzed by means of the mathematical statistics method. The results show that the mean value of the steep indexes of the north section, middle section and south section of Liupanshan Mountain is 65.11, 73.53 and 71.76, respectively. The change of the steep index of the channel is mainly affected by the difference of the uplift rate of the regional rock, and the influence of the related factors such as the rock formation, the rainfall and the river load in the study area on the steep index of the channel is small. The change of the steep index of the channel in each study area reflects the distribution of the uplift rate in different regions in the north and south of Liupanshan. The uplift rate of the north section of the Liupanshan Mountain is lower, the activity of the region is weak, the middle section is the fastest and the activity is strong, and the regional uplift of the south section is between the two. (6) Based on the investigation and analysis, the activity parameters of the eastern foot fault zone of the Liupanshan Mountain are analyzed, and the difference of uplift rate is constructed (? The comprehensive analysis of various parameters and data of the profile of UT, the geomorphology parameter (), the observation of the regional precision level and the profile of the level velocity and the geological profile of different sections is as follows: the uplift activity on the west side of the Liupanshan Mountain is stronger than that of the east side, The structural deformation and activity of the north section in the east-foot fault zone of the Liupanshan Mountain show a strong tendency. It is shown that the current GPS velocity profile shows the phenomenon of weak velocity gradient near the eastern foot fault zone of the six-plate mountain, but there is obvious stress accumulation, which may be the obvious stress transformation. The horizontal movement of the region is converted into the vertical motion dominated by the regional uplift, and the different sections of the fault zone and the two sides of the six-plate mountain have different vertical movement intensity.
【学位授予单位】：中国地震局地震预测研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P315.2
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