STRUCTURAL CONTROL ON ALTERATION AND MINERALIZATION IN LOW SULPHIDATION EPITHERMAL DEPOSIT MANTIKULORE AREA, PALU CITY, CENTRAL SULAWESI PROVINCE

• Main Author: Bilal Ghassan, Faza
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85835
• Institution: Institut Teknologi Bandung

Understanding the influence of geological structures on alteration and mineralization can be a determining factor in mineral resource exploration. The study area is located in the Mantikulore Area, Palu City, Central Sulawesi, covering an area of 51,5 km² and is within the kontrak karya area of PT Citra Palu Minerals. The Mantikulore Area is known to host low-sulfidation epithermal gold deposits based on alteration and mineralization characteristics. This study aims to understand the geological condition and the influence of geological structures on the distribution of alterasion and mineralization in the study area. The data used in this study were collected from field mapping and 52 rock samples, which were then analyzed through petrography, mineragraphy, atomic absorption spectroscopy (AAS), analytical spectral device (ASD), and geological structural analysis. The result of this study indicate that the research area comprises seven rock units, namely Amphibolite Schist, Biotite Gneiss, Granite Intrusion, Granodiorite Intrusion, Syenite Intrusion, Molasse Deposit, and Alluvial Deposits. Geological structures developed in the study area are classified into NE-SW and E-W trending right lateral strike slip faults, NW-SE trending left lateral strike slip faults, NW-SE trending normal faults, and NE-SW trending reverse fault. The alteration zones present in the study area include the kaolinite-illite zone (kaolinite – illite ± quartz ± alunite), smectite zone (smectite – illite ± quartz ± calcite), epidote-chlorite zone (epidote – chlorite ± quartz ± calcite), chlorite zone (chlorite ± quartz ± epidote ± calcite), and silisification zone. Mineralization in the study area is concentrated in quartz veins with the presence of Au, Ag, Cu, pyrite, and chalcopyrite. Alteration and mineralization in the study area exhibit characteristic of low-sulphidation epithermal deposit controlled by the prescence of three NW-SE trending quartz vein zones : Pondoh River Vein Zone, Hill 1 Vein Zone, and Hill 2 Vein Zone. These three vein zones were formed by NW-SE trending normal faults that served as pathway for the outflow of hydrothermal fluid in the study area.