MINERALOGICAL STUDY AND CHARACTERISTIC OF EPITHERMAL LOW SULPHIDATION DEPOSITS IN Mt. SENGUNGUNGKLUNG, NGADIREJO DISTRICT AND RINGINPUTIH DISTRICT, BLITAR REGENCY

• Main Author: ANDY YAHYA AL HAKIM (NIM : 22111001)
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/19887
• Institution: Institut Teknologi Bandung

Mt. Sengungklung, Ngadirejo and Ringinputih Districts located in the Blitar Regency. This area is a part of Southern Mountain of East Java, where the mineralization occurs in a Cenozoic as a product of the Sunda-Banda arc subduction. Mineralization from the outcrop contains the sulphide and copper mineral, which is mined by the local people. The aims of this study are to know the minerals composition from the microscopy analysis, to determine the ore condition, and to characterize the deposits based on the alteration and the mineralization studies. Data was obtained from the geological mapping, ore and waste rock sampling, altered rock and panned concentrate sampling. Samples have been prepared to analyze for mineragraphy and petrography, grain counting, SEM-EDS and element mapping analysis. <br /> <br /> <br /> <br /> The alteration in Mt. Sengungklung. was characterized by the presence of quartz-kaolinite, and the group minerals of quartz-plagioclase-chlorite-calcite-sericite, that indicated the advanced argillic alteration. Pyrophillite was identified by the SEM-EDS analysis, show the layered and schistose texture, meanwhile illite was identified in the fibrous texture and the rose like. In Ringinputih District, the argillic was identified by the presence of quartz-plagioclase-chlorite-actinolite-sericite and quartz-muscovite-kaolinite. SEM photomicrographs shows the presence of kaolinite with sheety texture. The alteration in Ngadirejo district was identified by the presence of quartz-plagioclase-dickite-muskovite-montmorillonite that indicated argillic-propilitic alteration. <br /> <br /> <br /> <br /> Ore minerals identified in Mt. Sengungklung was pyrite and galena with coarse grain size, and also chalcopyrite which occur as a inclusion in the galena. Mt. Sengungklung shows the advanced argillic alteration, that predicted not from the single source, because the presence of base metal minerals near with the surface, with intensively altered into advanced argillic alteration. In Ringinputih District, gold found as a inclusion in quartz, chloritization and sericitization found near with potassic and argillic alteration. In Ngadirejo district, malachite found as a secondary mineral from coper ore, and bornite was replaced by covellite near with the Guwo intrusion, predicted occur as different product of intrusion, which has different characteristic of ore mineral with other prospects. Mineralization was controlled by faults, and related with the flower structure type.