GEOLOGI DAN ALTERASI HIDROTERMAL DAERAH BLOK PANI DANSEKITARNYA, KECAMATAN BUNTULIA, KABUPATEN POHUWATO, PROVINSIGORONTALO.

• Main Author: Mangantjo, Syaifullah
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/78481
• Institution: Institut Teknologi Bandung

Study area is an exploration area of PT. Gorontalo Sejahtera Mining, which is located in the Region of Mount Pani, Buntulia District, Pohuwato Regency, Gorontalo. Previous researcher have stated that the mineralization type of this area is epithermal. To find the mineralization potential and geological conditions, the author are collaborating with companies doing geological mapping and hydrothermal alteration in the field. Based on literature studies, field observations, petrographic analysis, mineragraphy analysis, Geochemical analysis, secondary data analysis of ASD and ASSAY, the result is: This area is a volcanic complex that is composed of four units, the units are Volcanic Cones Unit, Pyroclastic Ridge Unit, Lava Ridge Unit and Alluvial Plain Unit. Drainage patterns are rectangular and radial, with V-shaped valley and intensive erosion. Stratigraphy of this area is composed of four lithologies unofficial from Late Miocene to Late Pliocene, in order from old to young, Granodiorite Unit, Dacite Lava Unit, Tuff Unit, And Dacite Intrusion Unit. Geological structure of shear faults are northwest-southeast and northeastsouthwest, its cut all the rocks from Late Miocene – Pliocene. The formation of shear faults in the study area produce hydrothermal cycle with dacite intrusion becomes heat source. Then hydrothermal solution reacts with wall rock through the cracks that have formed, resulting alteration and mineralization. Hydrothermal alteration zones that developed are Quartz-AdulariaChlorite-Smectite Zone, Illite-Smectite Quartz-Siderite Zones, Quartz-EpidoteChlorite-Calcite Zone And Chlorite-Mica-Quartz-Calcite-Pyropilite Zone. Sulfide minerals and base metal that presents are pyrite, calcopyrite, Arsenopyrite, Calcocite, and Sphalerite. There are veins that have a 0.5 to 3 cm thick, like chalcedony and quartz, with crystalline and crustiform texture. Based on the data, mineralization type in the study area classified as low sulphidation epithermal deposits. The mineralization is considered potentially to be further explored with further analysis of geophysical data of research area and content analysis of the vein, especially subpropyllitic alteration zone.