乐昌—霞葛MT剖面深部电性结构研究

为研究华南地区的壳幔电性结构,完成了华南地区乐昌—霞葛大地电磁测深剖面的探测,获得了该剖面的地电模型,并结合倾子、极化图和感应矢量等信息对地电模型进行了研究,对华南的电性结构、断裂特征和壳幔结构有了新的认识.研究结果表明:剖面上地壳西厚东薄,表面被大量的花岗岩高阻体所覆盖,6条断裂沿剖面展布.剖面两端岩石圈增厚,厚度超过100km,推测剖面西段岩石圈增厚是由于陆内挤压造山或陆内碰撞汇聚造山作用,而剖面东端的岩石圈增厚形成于大洋板块的俯冲;中部岩石圈减薄,厚度在60～80km之间,可能是与软流圈物质上侵有关.

The deep electrical structure of the Lechang-Xiage profile with MT method

In order to study the electrical structure of crust-mantle in South China,this study completes magnetotelluric sounding profiles detection in Lechang-Xiage,South China,acquiring the profile of the electrical structure model.It also studys the electrical structure combining tipper,the polarizing figure,the induction sensor model and other information thus gain new understandings of electrical structure,fracture characteristics and crust-mantle structure in South China.The results show that:the west part is thicker than the east part on the crust,which is covered by a lot of granite with high resistance body,and six fractures distribute along the profile.The lithosphere gets thick at both ends of the profile by 100 km.It is speculated that the thickness in the western part is due to intracontinental compression orogeny or intracontinental collision and convergence orogeny,while that of the eastern section is formed by oceanic plate subduction;the lithosphere gets thin in the central part by 60～80 km,which may relates to the intrusion of asthenospheric material.