论文部分内容阅读
红透山块状硫化物矿石主要成分为黄铁矿、磁黄铁矿、黄铜矿、闪锌矿和石英、角闪石、黑云母等脉石矿物。切成长40mm 直径17mm 的矿石圆柱用20wt%NaCl 溶液浸泡260小时后装入长江500型活塞-圆筒式三轴应力试验机,在362℃414MPa 围压下加1342MPa 轴压,13小时后于空气中自然冷却。实验后试样长度压缩为32.3mm,算得应变速率为4.1×10~(-6)/s。实验产物中出现大量垂直应力轴的松弛裂缝。黄铁矿强烈脆性破裂,而磁黄铁矿、黄铜矿和闪锌矿以塑性变形为主,局部也发生脆性破裂。再活化黄铁矿、磁黄铁矿和黄铜矿分别充填同种矿物的碎粒间隙。再活化产物也呈细脉穿插脆性变形的黄铁矿碎斑,细脉中以黄铜矿为主,其次是磁黄铁矿,有时含极少量闪锌矿,在磁黄铁矿、黄铜矿和闪锌矿的塑性变形区内,以及变形的石英和其它脉石矿物中均无再活化硫化物产出。实验结果表明在构造应力作用下强干性矿物和地质体容易发生脆性变形,从而为再活化成矿流体的运移和析出矿质提供通道和空间,而韧性变形区较难提供流体通道和矿质沉淀空间。所以,再活化成矿作用容易发生在脆性变形区和韧-脆性转换部位。原生矿石中的黄铜矿在实验条件下比其它三种硫化物更容易再活化。脆性变形的黄铜矿和黄铁矿比起其它矿物来更容易接受含铜流体的叠加,因此地层中的含铜黄铁矿矿胚层最容易受叠加流体作用而形成层控富矿床。
Hongtoushan massive sulfide ore is mainly composed of pyrite, pyrrhotite, chalcopyrite, sphalerite and quartz, amphibole, biotite gangue minerals. Cut into 40mm diameter 17mm ore cylinder soaked with 20wt% NaCl solution for 260 hours into the Yangtze 500-piston - cylinder triaxial stress testing machine, at 362 ℃ 414MPa confining pressure plus 1342MPa axial pressure, 13 hours after the air In the natural cooling. After the experiment, the sample length is compressed to 32.3mm, the calculated strain rate is 4.1 × 10 ~ (-6) / s. A large number of relaxed cracks in the vertical stress axis appear in the experimental product. Pyrite brittle fracture, and pyrrhotite, chalcopyrite and sphalerite mainly plastic deformation, partial brittle fracture also occurred. Reactivation of pyrite, pyrrhotite and chalcopyrite filled with the same kind of mineral particles gap. The reactivation products were also pyrochlore crushed with brittle deformation through fine veins. The chalcopyrite was mainly chalcopyrite, followed by pyrrhotite, sometimes containing very small sphalerite. In pyrrhotite, brass There is no reactivation of sulfides in the deformed zones of the mines and sphalerites, as well as in deformed quartz and other gangue minerals. The experimental results show that the strongly-dried minerals and geologic bodies are prone to brittle deformation under tectonic stress, so as to provide access and space for the reactivation of ore-forming fluids and the precipitation of mineralization, whereas the ductile deformation area is hard to provide fluid channels and mineral deposits space. Therefore, reactivation mineralization easily occurs in the brittle deformation zone and tough-brittle transition. Chalcopyrite in primary ore is more easily reactivated than the other three sulfides under experimental conditions. Brittle deformation of chalcopyrite and pyrite more than other minerals to accept the superposition of copper-containing fluid, so the formation of copper-bearing pyrite is most likely to be superposed by the formation of superimposed fluid layer stratabound rich ore deposits.