Dome-related gold mineralization in the Pani volcanic complex, North Sulawesi, Indonesia; a study of geologic relations, fluid inclusions, and chlorite compositions

Gold mineralization at the Pani prospect in north Sulawesi, Indonesia, is related to a Miocene or younger rhyodacitic volcanic center. The center, which is 3.5 km in diameter, consists of porphyritic lavas, intrusions, breccias, and pyroclastics. It overlies and partly intrudes horn-blende and hornblende-biotite granodiorite and Eocene (?) basaltic volcanics. Mineralization is spatially related to the Baganite dome, which is centered on Gunung Baganite. Low-grade (0.8 ppm) disseminated gold mineralization, associated with pyrite and minor base metals, is hosted by the dome. Silver mineralization (acanthite) occurs in minor quartz-hematite veins in overlying silicified pyroclastics. The most important gold mineral-ization occurs on the flank of the dome at the Pani ridge, less than 1 km from Gunung Baganite. It is associated with minor base metal sulfides, quartz, and adularia encrustations, found in vuggy fractures and centimeter-wide breccia zones, in weakly silicified rhyodacites, and in adjacent wall rocks. Quartz veins on the Pani ridge are virtually absent. The assemblage chlorite-albite-anatase-pyrite q-quartz-adularia is ubiquitous in flow-banded and massive rhyodacites in the prospect area, whereas carbonates occur within the enclosing pyroclastics. Strong si-