Mineralogical and geochemical characteristics of the Cu-Ag mineralization from the Kyaukse Sabe Taung deposit, western margin of the Shan Plateau, Myanmar

摘要

The Kyaukse Sabe Taung copper deposit is located in the western margin of the Shan Plateau, central Myanmar. It has estimated reserves of 1.6 Mt of ore grading 3.15% Cu, with additional Ag and Au enrichment. This deposit is typically hosted by Middle Ordovician limestone of the Wunbye Formation and the mineralization is controlled by the regional structures. The ore-mineral assemblage consists of pyrite, chalcopyrite, tetrahedrite, chalcocite, covellite, bornite, native copper, malachite, azurite, cuprite, tenorite, silver amalgams and Bi-sulphosalts, members of hammarite-aikinite series. Gangue minerals are quartz, dolomite, ankerite and calcite. Silver mineralization is represented by acanthite and by silver amalgams with a high content of Hg, ranging from 2.15 to 26.68 wt.%. Silver minerals are a result of supergene alteration of Ag- and Hg-bearing tetrahedrite and could increase economic value of the deposit. Silver association is located within the lowermost part of the supergene zone in the deposit, and tracking the redox barrier position can help to identify parts of the orebody with silver enrichment. The delta S-34 values of chalcopyrite are +5.7 to +10.7 parts per thousand and those of tetrahedrite are +1.6 to +1.7 parts per thousand.