Abstract:

The Sakai area in Sang Thong district, Vientiane city, Laos is considered to have prospects for primary gold mineralization, with 12 ore bodies discovered. The synthesis of research results shows that the geological formations in the Sakai area range from the Paleozoic to the Cenozoic era. The primary gold ore bodies in the Sakai area have complex shapes and are often found in fractured and altered rhyolite and tu? rocks, controlled by the Phu Dao fault systems. Gold ore is distributed in the Triassic continental formations, speci?cally in the lower-middle section (T1-2). The lithologic components include conglomerate, sandstone with impurities, gray-colored siltstone, sandy limestone, gray-colored limestone, dacite, ryodacite, white-colored felsite, rhyolite, and tu?. The main minerals associated with the primary gold ore in the study area are native gold, accompanied by quartz. The native gold is disseminated in sphalerite or occurs as veinlets associated with pyrite ?lling fractures in quartz. Primary minerals include pyrite, arsenopyrite, native gold, sphalerite, galena, and occasionally chalcopyrite and tennantite. Secondary minerals include goethite, azurite, and malachite. Non-ore minerals include quartz and barite. Based on the regional geological history and the magmatic history of ore genesis, the gold mineralization in the Sakai area is preliminarily interpreted as a late-stage type of gold mineralization related to the P-Tage magmatism and mineralization phase, which is prominent in the Loei orogenic belt.