论多因复成矿床的形成机理

摘要

This paper reviews the ore-forming mechanism of polygenetic ore deposits in the basis of intergrating the latest progresses on modern continental dynamics and geodynamics, and their applications to geoscientific system, and discusses the metallogenetic processes of a few of typical ore deposits in China. We suggest that the post-Platform Activated Region (i.e. the Diwa Region) proposed by Prof. Chen Guoda should be referred in particular to the regions akin to the east China continental crust that was characterized by large-scale tectono-magmatism and associated metallogeny during the Mesozoic. Because of the genetic link to the geotectonic and geodynamic evolution, and the particularity and/or some differentiation of crustal evolution and related multistage geotectonic development, associated metallogenesis shows polycyclic nature, particularity and/or superimposed reworking and enrichment. The post-Platform Activated (Diwa) regions are characterized by multistage geotectonic development which was accompanied by large-scale tectonometamorphic, tectonomagmatic and tectonothermal (fluid) events, thus ore deposits in these regions are also polygenetic and generally resulted in the high-grade polygenetic ore deposits which are of great economic significance. We, therefore, propose that the polygenetic ore deposits are products of multiple geological processes including sedimentation, tectonic deformation, magmatism, metamorphism and concomitant large-scale fluid activities. As for ore-forming mechanisms, this type of ore deposit is likely resulted from multistage crust-mantle interactions. Finally, we suggest that the future research on polygenetic ore deposits shall focus on the ore-forming dynamic mechanism and related physicochemical processes.%结合现代大陆动力学与地球动力学最新理论与研究和应用进展，以及国内几个典型矿床的成矿实例分析，本文重新审视了地台活化区(即地洼区)多因复成矿床的形成机理。作者认为，陈国达先生所研究的地台活化区应特指中国东部或全球类似地区大地构造发展至中生代时期因发生强烈构造–岩浆活动和相关成矿作用而在大陆地壳的表现。由于成矿作用与大地构造发展和/或地球动力学事件具有密切的成因联系，以及由于地壳演化及其大地构造发展阶段还具有独特性或存在某些差异，成矿作用从而表现出多旋回性、特殊性或叠加改造和富化特点；特别是，地台活化区往往包含多大地构造发展阶段，并发生大规模构造变形、岩浆活动和变质作用等构造–岩浆–热(流体)事件，因而这种活化构造区内的成矿作用往往具有多因复成成矿特征，并形成了具有经济意义的、大而富的矿床。实质上，多因复成矿床是多地质过程包括沉积作用、构造变形、岩浆作用和变质作用及伴生的大规模流体事件等耦合的产物，其动力学机制可能来源于(多期或幕式)地幔(柱)对流和上涌及壳‒幔相互作用或地幔柱–岩石圈板块相互作用。作者最后指出，多因复成矿床今后的研究重点仍应关注其成矿动力学机制与过程。