| 长江下游地区布格重力异常及深浅部构造特征 |
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| 引用本文： | 田语堂,王鑫,张景发,李忠.长江下游地区布格重力异常及深浅部构造特征[J].地球物理学进展,2020(3):874-881. |
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| 作者姓名： | 田语堂 王鑫 张景发 李忠 |
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| 作者单位： | 防灾科技学院;中国地震局地壳应力研究所 |
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| 基金项目： | 北京市自然科学基金资助项目(8184090);吉林省科技发展计划(20180201034SF)共同资助 |
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| 摘 要： | 为研究长江下游地区地壳结构及深浅部构造特征,本文选用大比例尺布格重力数据,利用小波变换方法进行场源分解处理,剖析不同深度下地壳横向结构,采用Parker变密度模型反演该地区的莫霍面深度,并构建两条地壳密度结构剖面模型,对研究区深、浅部构造进行精细刻画.结果表明,长江下游地区重力场整体呈现NE走向的构造异常,多发育NE向的断裂及隆凹构造.沉积层至上地壳的地壳结构复杂,存在数量较多的小尺度的线性重力梯度条带,形成了15条明显的以NE、NNE方向为主体的构造单元以及2条NW向区域性断裂,多数断层延伸至中地壳;在中、下地壳尺度中,断裂带多沿高、低异常梯度条带分布,其中金坛-南渡断裂与茅山断裂合并,形成规模一条较大的控制性断裂,推断该断裂已经切穿上地幔,结合地震数据发现,两条断裂的相接处在近代以来地震活动性较强,此外茅山断裂在深部向北延伸至镇江市区,受无锡-宿迁断裂带影响截止于埤城附近.区域莫霍面深度分布在31.6~33.4 km,表现为以埤城断凸为中心,东西浅,南北深的‘X’状.
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| 关 键 词： | 长江下游地区 布格重力异常 地壳结构 莫霍面 重力建模 |
Bouguer gravity anomaly and structural features in the lower reaches of the Yangtze river |
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| TIAN Yu-tang,WANG Xing,ZHANG Jing-fa,LI Zhong.Bouguer gravity anomaly and structural features in the lower reaches of the Yangtze river[J].Progress in Geophysics,2020(3):874-881. |
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| Authors: | TIAN Yu-tang WANG Xing ZHANG Jing-fa LI Zhong |
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| Institution: | (Institute of Disaster Prevention,Yanjiao 101601,China;Institute of Crustal Dynamics,China Earthquake Administration,Beijing 100085,China) |
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| Abstract: | For the study of the Yangtze river downstream of the earth's crust structure and the depth of tectonic characteristics,this paper chooses the larger scale of bouguer gravity data,using wavelets multi-scale analysis method to analyze gravity data,analysis of different depth under the earth's crust horizontal structure,at the same time using Parker variable density model inversion moho depth,and build the two crustal density structure profile model to describe the deep and shallow structure.The study shows that the gravity field in the lower reaches of the Yangtze river presents the tectonic anomaly of NE trend,and many NE trend faults and uplifts and depressions.The crustal structure of the sedimentary layer to the upper crust is complex,and a number of small-scale linear gravity gradient bands,forming 15 obvious NE or NNE tectonic units and 2 NW trending regional faults,most of which extend to the middle crust.In the middle and lower crust,faults distribution along the high and low gradient,fault of Jintan-Nandu combined with Maoshan fault,forming a large-scale controlling fault.It is inferred that the fault has cut through the upper mantle.The Maoshan fault zone extended northward to Zhenjiang urban area in the deep part and is affected by the Wuxi-Suqian fault zone,where it ended near the Picheng city.The depth of Moho surface in the study area ranges from 31.6 km to 33.4 km,showing an‘X’shape,which is characterized by the center of the Picheng city,shallow east-west and deep north-south. |
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| Keywords: | Lower Yangtze Bouguer gravity Crustal structure Moho interface Gravity modeling |
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