无外加流体、350℃和差异应力条件下硫化物再活化实验研究

Remobilization experiments of sulphides under differential stress at 350℃ without addition of external water

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。将此矿石烘干后作为试料置于岩石三轴应力试验机,在13h内将轴压、围压和温度分步升至1276MPa、414MPa和350°C,然后在空气中自然冷却至室温。实验产物中黄铁矿、石英、长石等以脆性碎裂为主,而磁黄铁矿、黄铜矿、闪锌矿和云母等以塑性变形为主。再活化的黄铜矿、磁黄铁矿和少量闪锌矿呈脉和网脉穿插黄铁矿碎斑。实验结果表明,即使没有外来流体加入,构造动力作用所导致的流体包裹体破坏所释出的流体,就足以使成矿物质发生活化转移和再活化。

The massive sulphide ore from the Hongtoushan deposit are composed mainly of pyrite, pyrrhotite, chalcopyrite, sphalerite, quartz, hornblende and biotite. As starting material, the ore was dried and mounted in a tri-axial stress machine. The experiment started with stepwise raise of axial pressure, confining pressure and temperature, and stopped when these parameters reached 1276 MPa, 414 MPa and 350℃, respectively. Then, the sample was cooled in air to room temperature. The run product was characterized by cataclasis of pyrite and quartz, and plastic deformation of pyrrhotite, chalcopyrite, sphalerite and mica. As veins and networks, remobilized chalcopyrite, pyrrhotite and minor sphalerite cut pyrite porphyroclasts. This experiment shows that fluids released by fluid inclusions in response to tectonic stress are sufficient to cause mobilization and remobilization of ore materials even though no external water is added.