PARAGENESIS MINERAL DAN INKLUSI FLUIDA PADA ENDAPAN EPITERMAL, AREA MAIN RIDGE DAN OSELA, DISTRIK BAKAN, SULAWESI UTARA

Abstract

This research was conducted to determine mineral paragenesis and the characteristics of hydrothermal fluids which form high sulfidation epithermal deposits. The research was conducted in the Main Ridge and Osela areas, Bakan Distict, Motandoi Village, East Pinolosian District, Bolaang Mongondow Regency, North Sulawesi Province. Research methods include megascopic petrology, petrographic, mineragraphic, geochemical and fluid inclusion analysis. The association of minerals, intensive silicification process and vuggy textures indicate the presence of high sulfidation epithermal mineralization. In the Main Ridge area the range content of Au 0.4-1 g/t, Ag 1-3 g/t, Cu 5-63 g/t, Pb 5-55 g/t, Zn 4-5 g/t, whereas in the Osela area the range content of Au 1-89.4 g/t, Ag 4-33 g/t, Cu 306-403 g/t, Pb 30-120 g/t, Zn 14-41 g/t, the pattern corresponds to the presence of euhedral pyrite, chalcopyrite and enargite-luzonite in the Osela area and not present in the Main Ridge area. Main Ridge area has homogeneity temperature (Th) 212 ^oC, salinity 2.5 wt. % NaCl eq., and mineralization depth 210 m, in the Osela area it has Th 267 ^oC, salinity 2.9 wt. % NaCl eq., and mineralization depth 620 m. Fluid inclusion data indicate the mixing of hydrothermal fluids that develop in the Main Ridge area, while the Osela area shows the dilution of hydrothermal fluids during the process of fluid evolution.