摘要
深地震反射剖面技术以其探测精度高的优势被作为岩石圈精细结构研究的先锋技术,并在全球典型矿集区结构探测中发挥了重要作用.为深入研究青藏高原碰撞造山成矿系统深部结构与成矿过程,本文系统总结了深地震反射技术发展现状,梳理了该技术在加拿大、澳大利亚、中国、俄罗斯、瑞典等全球多个国家的典型矿集区的应用实例,归纳总结了地壳深部结构对矿集区控矿因素的影响,阐述了地壳、上地幔深部结构与深部成矿过程的关系.从全球实例看,深地震反射剖面探测成果为大型矿集区的形成提供了深部线索,反射透明区可能是地幔流体向上运移通道,形成矿集区的成矿物质与能量来源,表明地幔物质参与了成矿作用;具有很强反射特征的断裂系统,包括大型断层、滑脱面和剪切带,是成矿流体从下地壳向上迁移的通道;矿集区深地震反射剖面中"亮点"反射可能是火山活动的深部岩浆上涌至中地壳后而形成的残余岩浆囊的反映.揭露精细的矿集区深部结构不但对矿集区构造历史演化的重建具有重要作用,还对未来成矿潜力和前景靶区的确定具有重要指导意义.
Deep seismic reflection profile has been used as the pioneering technology in the study of lithosphere fine structure because of its high detection accuracy and also has played an important role in the structural detection of typical mining areas around the world. In order to study the deep structure and the metallogenic process of the collision orogenic metallogenic system on the Qinghai-Tibet plateau, in this paper, the development status of deep seismic reflection technology is summarized systematically, and the application cases of this technology in typical ore concentration areas in Canada, Australia, China, Russia and Sweden are combed. The influences of deep crust structure on ore-controlling factors in ore centration areas and the relationships between the structure of crust and upper mantle at depth and the deep metallogenic process are illustrated. According to the global examples, the detection results of deep seismic reflection profile provide deep clues for the formation of large ore concentrated areas. The reflective transparent zone may be the upward migration channel of the mantle fluid, forming the mineral and energy sources of ore concentration area, indicating that the mantle material is involved in mineralization. Fracture systems characterized by strong reflectivity, including large-scale faults, detachments and crustal shear zones, are pathways through which metallogenic fluids migrate upward from the lower crust. The"bright spot"in the deep seismic reflection profiles of ore concentrated areas may be the reflection of the residual magma chamber formed after the deep magma of volcanic activity surges into the middle crust. Revealing the deep fine structure not only plays an important role in the reconstruction of the tectonic historical evolution of ore concentration area, but also has crucial guiding significance for the determination of the future metallogenic potential and the target area of the foreground.