MINERALIZATION PARAGENESIS STUDY OF LOW SULFIDATION EPITHERMAL DEPOSIT IN NIRMALA AREA, BOGOR REGENCY, WEST JAVA PROVINCE

• Main Author: Farras Hadikusumo, Muhammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69533
• Institution: Institut Teknologi Bandung

The research area is located in the Nirmala Area, Nanggung District, Bogor Regency, West Java Province and is a part of a Mining Business License managed by PT. Aneka Tambang Tbk. The research area has an area of 2.53 ????????2 and is mostly located within the Gunung Halimun Salak National Park. This research was conducted to determine the geological condition, distribution of alteration, determine the presence of mineralization, and mineralization paragenesis in the research area based on rock samples taken. The research was conducted by taking 54 rock samples. The methods used in this research are geological and alteration mapping, thin section petrographic analysis, mineragraphy analysis, specTERRA analysis, XRD analysis, and Assay AAS analysis. The research area consists of two lithological units, namely the Tuff – Breccia Unit 1 and the Tuff – Breccia Unit 2. The research area consists of four geomorphological units, namely the Ci Talahap Pyroclastic Flow Hills Unit, Ci Malang Pyroclastic Flow Hills Unit, Ci Sangku Pyroclastic Flow Hills Unit, and Ci Langgar Pyroclastic Flow Hills Unit. The main orientation of the lineaments in the research area is ENE - WSW and the vein lineaments found in the research area are NW – SE. There is one geological structure in the research area, namely a left shear fault trending NE – SW. The alteration zone in the study area is divided into two zones, namely the Quartz + Kaolinite ± Illite ± Smectite (argillic) Alteration Zone and the Quartz ± Chlorite ± Smectite ± Illite ± Albite ± Calcite (propylitic) Alteration Zone. Mineralization paragenesis in the study area is divided into two stages of mineralization, namely the first phase starting with the appearance of the mineral’s sphalerite, galena, magnetite, rutile, chalcopyrite, pyrite, and covellite. Then the second phase is the oxidation weathering phase which is characterized by the appearance of iron oxide minerals (HFO). Based on the presence of ore minerals and gangue minerals, the type of deposit in the research area is an epithermal low sulfidation deposit.