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收集了安徽、江西、浙江、江苏、湖北和河南6个省的区域地震台网138个宽频地震台站以及中国地质大学(北京)在长江中下游成矿带布设的19个流动宽频地震台站的三分量背景噪声数据,利用背景噪声面波层析成像方法,获得了长江中下游成矿带及其邻区地壳三维剪切波速度结构和径向各向异性特征.首先获得了5~38s周期的瑞利波和勒夫波相速度,结果显示短周期(<16s)的瑞利波和勒夫波相速度与研究区内的主要地质构造单元具有良好的相关性,但在中长周期(20~30s)瑞利波相速度显示大别造山带东部为明显低速特征,而勒夫波相速度并未表现出异常特征.研究区域地壳三维有效剪切波速度和径向各向异性结果显示:苏北盆地和江汉盆地上地壳都表现为低速和正径向各向异性特征,华北克拉通东南部也表现为正径向各向异性,这可能与盆地浅部沉积层的水平层理结构相关.大别造山带中地壳显示为弱的正径向各向异性,同时其东部下地壳显示为低剪切波速度和强的正径向各向特征,可能是由于其在造山后发生了中下地壳的流变变形,引起各向异性矿物近水平排列所导致的.长江中下游成矿带内的鄂东南和安庆—贵池矿集区中地壳弱的负径向各向异性可能是由于深部岩浆向上渗透时所产生的有限应力导致结晶各向异性矿物的垂直排列所引起的.整个长江中下游成矿带下地壳都表现出正径向各向异性特征,可能是由于在伸展拉张的构造作用力下,下地壳矿物的晶格优势水平排列所引起的.
138 broadband seismic stations of regional seismographs in 6 provinces of Anhui, Jiangxi, Zhejiang, Jiangsu, Hubei and Henan provinces and 19 mobile broadband seismic stations deployed in the metallogenic belt of the middle and lower reaches of the Yangtze River by China University of Geosciences (Beijing) And the background noise surface wave tomography method was used to obtain the 3D shear-wave velocity structure and radial anisotropy of the crust in the metallogenic belt and its adjacent areas in the middle and lower reaches of the Yangtze River.Firstly, Periodic Rayleigh wave and Love wave phase velocities. The results show that the Rayleigh wave and the Love wave phase velocities of the short period (<16s) have a good correlation with the main geological tectonic units in the study area. However, (20 ~ 30s) Rayleigh wave velocity shows the eastern part of the Dabie orogenic belt is obviously low-speed features, and the Love wave phase velocity does not show the anomalous characteristics of the study area of the earth’s crust three-dimensional effective shear wave velocity and radial anisotropy results The results show that both the upper crust of the Northern Jiangsu Basin and the Jianghan Basin show low-velocity and positive radial anisotropy, and the southeastern part of the North China Craton also shows a positive radial anisotropy, which may be related to the horizontal bedding structure of shallow sedimentary layers in the basin Related The middle crust of the Dabie orogen shows a weak positive radial anisotropy, while its eastern lower crust shows low shear-wave velocity and strong positive radial anisotropy, probably due to its occurrence after orogeny The deformation of the lower crust is caused by the near horizontal arrangement of anisotropic minerals.The weak negative radial anisotropy of the crust in the southeastern Hubei and Anqing-Guichi ore areas in the metallogenic belt of the middle and lower reaches of the Yangtze River may be attributed to The limited stress caused by the upwards permeation of deep magma results in the vertical alignment of crystalline anisotropic minerals, and the lower crust in the middle and lower reaches of the Yangtze River shows a positive radial anisotropy, probably due to the extensional tension Under the tectonic force, the lower crustal minerals are caused by the arrangement of their lattice predominance levels.