Geological Characteristics and Preliminary Genesis Exploration of the Sakay Gold Deposit in Vientiane, Laos

The Sakay gold deposit in Vientiane, Laos, is located in the Indochina landmass of the southeastern segment of the Tethys orogenic belt, specifically within the Vientiane-Pakse micro-landmass and the Vientiane-Pakse metallogenic belt. This area is regionally significant for the concentration of minerals such as gold, copper, and tin. The host rocks of the deposit are intermediate volcanic lavas and volcanic tuffs, occurring in near-east-west brittle shear structural fractures through hydrothermal filling and metasomatism. The ore exhibits granular texture, subhedral texture, porphyritic texture, and oriented polycrystalline texture, with structural features such as disseminated, vein-like, and cataclastic breccia. The main ore minerals are pyrite, sphalerite, galena, and chalcopyrite, while the gangue minerals are primarily quartz, calcite, and dolomite. Gold is mainly present as included gold or fissure gold within the crystal lattices and microfractures of minerals such as pyrite and sphalerite. Based on mineral assemblages and generation timing, the mineralization can be divided into three stages: arsenopyrite-pyrite-dolomite-quartz (I), sphalerite-galena-chalcopyrite-calcite (II), and siderite (III), with the latter stages often overlaying the former, showing evident cross-cutting and metasomatic phenomena. The surrounding rocks in the mining area are altered, mainly showing silicification, carbonatization, limonitization, sericitization, and chloritization. Preliminary studies suggest that this deposit is a low-temperature hydrothermal gold deposit within a brittle shear zone.