粤东地区中生代金属矿床的成矿机制

在前人大量系统和深入的成矿地质背景和成矿地质地球化学研究的基础上,根据粤东地区锡、钨、铜、银、金多金属矿床(点)区域成矿作用特征,着重探讨了在中生代花岗质火山-侵入杂岩岩浆作用的背景下,成矿元素的富集过程及成矿物质的迁移、沉淀机制.研究认为,成矿物质的富集经历了地壳岩石的选择性部分熔融、花岗质岩浆分异、流体-熔体分馏和流体与流经岩石相互反应(水-岩作用)4个阶段.由于作为热源的岩浆熔体的存在及不同成因断裂裂隙构造的产生,富含成矿元素的岩浆热液流体上升,并与深循环的大气降水热液混合,形成热液对流体系.在长期的热液对流循环中,随着构造脉动和物理化学条件的改变,沉淀出不同阶段的矿石,并在不同的构造部位和围岩中形成不同类型的矿床.

Metallogenetic mechanism of Mesozoic metallic ore deposits in eastern Guangdong area

On the basis of the systematic and thoroughgoing studies by the predecessors on the metallogenetic geological background and geochemical characteristics of the polymetallic ore deposits of tin, tungstern, copper, silver and gold in eastern Guangdong area, this paper emphatically goes further into the regional mineralization characteristics, the enrichment process of ore-forming metal elements and the migration and sedimentation mechanism of ore-forming material in the background of the magmatism of Mesozoic granitic volcanic-intrusive complexes. It is concluded that the enrichment process of ore-forming metal elements went through four stages metataxis of crustal rocks, magmatic differentiation, fluid-melt fractionation and water/rock reaction. And it is indicated that the hydrothermal fluids sedimentated to form ore minerals in different stages and formed different ore deposit types because of the long term hydrothermal convection, tectonic pulsation and the changing of physicochemical condition.