韧性剪切过程中的物质迁移及其成矿意义

Mass migration in ductilitic shear process and its ore-forming implications

老湾金矿床赋矿围岩是经历过多次韧脆性剪切改造作用的中元古界龟山组变质岩系,主要岩石类型为二云石英片岩和斜长角闪片岩。成矿作用发生于燕山晚期,此2类主要岩石类型在矿化后形成2类不同的矿石类型。文章选取矿区远离矿体的不同类型的赋矿围岩进行质量平衡的计算和分析,探讨了在成矿前的韧性剪切变形变质过程中物质的带出带入及其对成矿作用的物质贡献,结果表明,老湾金矿床的赋矿围岩在此过程中成矿物质即已伴随硅质和碱质的迁入而得到了富集。

The host wall-rocks of the Laowan gold deposit are metamorphic rock series of Middle Proterozoic Guishan Formation which had undergone multiple deformation and metamorphism of ductilitic-brittlitic shear. The main rock types are two-mica quartz schist and plagioclase amphibole schist. After ore-forming, the two types of rocks took place strong alteration and mineralization and formed two different ore types. In this paper, the migration and source of the metallogenic material are discussed based on the mass balance calculation and analysis of the two different host wall-rocks in the processes of ductilitic shear. And it is concluded that the metallogenic material of the host wall-rocks were enriched initially in ductilitic shear process.