Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

Antimony deposits in the Ha Giang and Quang Ninh areas, northern Vietnam, were formed in epithermal veins and stockworks which fill the fault fractures in Paleozoic to Mesozoic metasedimentary rocks. Ore mineralogy exhibits very simple and similar mineral assemblages, consisting exclusively of quartz and stibnite. Simple vein mineralogy is characteristic of worldwide epithermal antimony deposits. Mineralogic and fluid inclusion data indicate that the antimony mineralization in the two areas occurred at the temperature and salinity ranges of 130o to 180oC and 0.6 to 5.2 wt.% NaCl equiv.. The relationships between homogenization temperature and salinity data indicate that antimony mineralization was mainly a result of fluid boiling and successive meteoric water mixing at depths of about 200 m for the Ha Giang area, and of simple cooling for the Quang Ninh area. Calculated total sulfur values of hydrothermal fluids(d34SSS = -8.2~3.5‰) reflect an igneous source of sulfur. Measured and calculated hydrogen and oxygen isotope values of hydrothermal fluids indicate the mixing of highly exchanged meteoric water with less exchanged meteoric water.