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

Abstract：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°C, 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.