华南地区进贤-柘荣剖面深部电性结构

为了研究华南地区的深部电性结构,探寻浅部地质过程的深部背景,布设了江西进贤至福建柘荣超长周期大地电磁测深剖面。通过剖面数据的处理、定性分析及二维反演,获得剖面岩石圈尺度的电性结构模型,并分区块对壳幔电性结构及主要断裂进行了分析。反演结果表明:1)剖面可分为4个构造单元,分别为江南造山带、华夏地块内部、华夏褶皱带和东南沿海岩浆岩带;2)武夷山与东南沿海岩浆岩带两处电性莫霍面隆起,电性莫霍面的起伏特征受控于区域深大断裂;3)剖面电性岩石圈整体表现为西薄东厚,江南造山带岩石圈-软流圈界面埋深为80~100 km,华夏褶皱带及东南沿海岩浆岩带的岩石圈-软流圈界面埋深约为140 km,存在一处岩石圈减薄区和两处软流圈上涌区,反映了伸展构造作用对岩石圈的不均匀改造。

Deep Electrical Structure of Jinxian-Zherong Magnetotelluric Profile in South China

In order to study the deep electrical structure in south China,and explore the deep background of the surface geological process,we have accomplished a long-period magnetotelluric profile from Jinxian,Jiangxi to Zherong,Fujian.Based on the data processing,2D qualitative analysis and 2D inversion,the lithospheric electrical structure model was finally obtained.The electrical structure of four tectonic regions and major faults were analyzed.The inversion model reveals:1 )the profile can be divided into four tectonic regions,which are the Jiangnan orogen,the Cathaysia interior,the Cathaysia folded belt and the Southeast coast magmatic belt,respectively.2)Two electrical Moho uplifts were found in Mount Wuyi and the Southeast coast magmatic belt,and the electrical Moho was controlled by major faults.3)The lithosphere thickness of the profile gets thinning from east to west on the whole. The thickness of the lithosphere asthenosphere boundary of Jiangnan orogen varies from 80 to 100 km, the thickness of the lithosphere-asthenosphere boundary of Cathaysia folded belt and the Southeast coast magmatic belt is about 140 km.There exists one lithosphere thinning region and two asthenophere upwelling areas,which reflects the nonuniform reform of the lithosphere under the tectonic extension process.