滇西保山金厂河铜锌铁矿区构造演化过程及其成矿/控矿作用

Tectonic Evolution and Ore-control Structure of the Jinchanghe Copper Zinc Iron Deposit in Baoshan,Western Yunnan

金厂河矽卡岩型铜锌铁多金属矿床,位于三江构造带保山地块北部,其展布受地层与褶皱‒断层构造系统共同控制。本文对矿区地表外围以及深部坑道出露的构造进行详细研究,分析构造变形作用过程,总结构造成矿/控矿规律。研究表明,矿区至少经历五期构造变形过程:第一期SN向正断层为先存导矿构造,控制了矿床的基本空间分布;第二期SN向纵弯褶皱及NE、NW向共轭断层,是成矿期控矿构造,直接控制了成矿流体贯入和聚集沉淀;第三期为NE-SW向断褶带,区域挤压隆升,矿体被改造并抬升至浅部;第四期NW向褶皱与第二期褶皱横跨叠加,形成穹窿构造;第五期为NW向阶梯式左行正断层,破坏矿体连续性。成矿过程中,硅钙面为后生矿床层状就位提供赋存条件,断层是矿液运移聚集的重要通道,背斜核部及西翼是矿体主要容矿空间,断层泥、泥岩层、断层上盘及辉绿岩等不透水层共同组成矿液圈闭。

The Jinchanghe Cu-Zn-Fe polymetallic deposit is located in the northern Baoshan block of the Sanjiang tectonic zone.It consists of stratabound and fault-controlled orebodies.Based on field investigation and deep tunnel cataloging,the spatial distribution,movement style and mechanical properties of the pre-ore,syn-ore,and post-ore structures were determined,and the ore-controlling regularities of the deep structures are summarized.Detailed structural analysis shows that the tectonic evolution of the mining area can be divided into at least five stages of tectonic deformation.The first stage of N-S striking normal fault is the ore-conducting structure,which controls the general spatial distribution of the orebodies.The second stage N-S trending buckle fold and NE\NW striking conjugate fault are the syn-ore structures,which provide storage space for the flow and accumulation of ore-forming fluids,and are the main ore controlling structures.The third stage NE-SW striking thrust faulting resulted in the regional compression uplift,and the orebodies were deformed and uplifted to the shallow level.The fourth stage NW trending folding superimposed the second stage fold,forming the Jinchanghe dome.The fifth stage NW striking stepped left lateral normal fault cut through the orebodies.During mineralization,the Si/Ca boundary provides space for ore body emplacement,the faults act as important channel for ore fluid migration and accumulation,for instances,the core and west wing of the anticline are the main ore-bearing spaces,and the impermeable layers such as the fault mud,the mudstone layer,the fault hanging wall,and the diabase constitute the ore fluid traps.