黔西北铅锌多金属矿集区成矿构造体系及其控矿机制

黔西北矿集区作为川滇黔铅锌多金属成矿区的重要组成部分,构造控矿-成矿机制一直是该区深化研究的热点和难点。针对长期困扰该区铅锌矿床成矿理论提升和制约深部找矿突破的构造研究瓶颈,基于10个主要铅锌矿床的矿体赋存规律研究,运用矿田地质力学理论和方法,解析了成矿构造的几何学、运动学、力学等特征,识别和厘定了该区存在五种控矿构造组合样式:正断层-背斜式、双向断层-背斜组合式、同向斜落走滑-断褶构造组合式、反倾断层-背斜式、同向斜冲走滑-断褶构造组合式。结合典型矿床构造控矿规律和地球物理深部探测等信息,研究认为,自印支期以来,该区构造体系呈现从NE构造带→NW构造带→SN构造带(构造体系)的成生发展过程。其中,NE构造带为黔西北铅锌矿集区的成矿构造体系,进而论证了构造控矿作用机制,构建了构造控矿模式,为区域勘查部署和深部找矿突破提供了理论依据。

Ore- controlling mechanism of NE- trending ore- forming structural system at Zn- Pb polymetallic ore concentration area in northwestern Guizhou

Ore-controlling and ore-forming mechanism of structure has always been one of research hotspots and difficulties in the northwest Guizhou ore concentration area,which is an important part of the SichuanYunnan-Guizhou poly-metallic metallogenic domain.Aiming at the structural research bottlenecks that has been troubling the mineralization theory of lead-zinc deposits in this area and restricting the breakthrough of deep ore-prospecting for a long time,based on the structural analysis of 10 major Zn-Pb deposits,including analytic geometry,kinematics and mechanical properties by Theory and Method of Orefield Geomechanics,the five types of ore-controlling structure combination types,these are normal fault-anticline type,both direction faults-anticline combination type,synclinal faults-anticline combination type,anti-dip fault in different vertical positions-anticline type and synclinal reverse faults-anticline combination type,have been identified and determined.Combined with the structural ore-controlling regularities of major deposits and deep geophysical exploration and the other information,the genic development processes of structural systems in this area have underwent three stages since the indo-china period,including Northeast-trending tectonic system→Northwest-trending tectonic system→North-southtrending tectonic system.In these systems,North-eastern-trending tectonic system is the metallogenic tectonic system.On the basis of demonstrating the structural ore-controlling mechanism,the structural ore-controlling model of Zn-Pb deposits in northwestern Guizhou has been established.These studies provide a theoretical basis for regional exploration deployment and deep prospecting breakthrough of deposits in the future.