构造形变类型与金矿化类型的关系

Relation Between Types of Structural Deformation and Gold Mineralization

含金构造形变类型决定或控制金矿化类型 ,深层次的韧性超韧性变形为元素迁出区 ,一般不利于金矿化 ;韧性含金构造控制蚀变糜棱岩型金矿化 ,韧脆性变形含金构造控制构造蚀变岩型金矿化 ,脆性含金构造控制石英脉型金矿化。对于韧性剪切带和未发生叠加蚀变矿化的糜棱岩来说 ,往往是构造变形越强 ,金元素含量越低。但在蚀变糜棱岩型金矿床中 ,已经叠加蚀变矿化的糜棱岩若构造变形越强、构造差应力越大 ,金元素含量越高。而且含金构造中岩石的组构特征、糜棱岩类型、应变幅度、石英变形机制与金矿富集程度都有密切的关系。构造带和造山带的演化 ,导致韧性剪切带不断抬升剥蚀 ,并在其上叠加韧脆性和脆性变形 ,也相对应发生不同类型金矿化的叠加 ,多阶段的构造和金矿化的叠加 ,构成复杂的矿化类型叠加组合型式或反序现象。这正是形成大型特大型金矿床的重要条件。

The types of Au-bearing structures control over the type of gold mineralization. Deep-level ductile shear deformation is unsuitable to gold mineralization, where the Au-element is remobilized by ductile shear deformation, and migrating out from the domain. The ductile Au-bearing structure control over altered mylonite type of gold mineralization; ductile-brittle Au-bearing structure control over structural altered rock type; and brittle Au-bearing structure control over quartz vein type. In non-mineralized mylonites of a ductile shear zone, the stronger of ductile shear deformation, the lower of the gold abundance. In contrast, in mineralized mylonite, the stronger of ductile shear deformation, the higher of the gold abundance, and there is a positive correlation between gold abundance and value of the structural differential stress. The gold abundance is also related to the type of mylonite, the feature of micro-fabric, the mechanism of quartz deformation and the size of strain. The development of a structure zone and the doming of the orogenic belt cause the ductile shear zone being uplift and denuded, and there happens a superimposion of ductile-brittle an brittle deformation onto the ductile deformation. Similarly, the superimposion of the type of gold mineralization occurs. These result in a very complex assemblage type of the gold mineralization. And it is also the suitable factors for forming a large-scale gold deposit.