Geologi, Alterasi dan Mineralisasi Endapan Porfiri pada Area \"X\", Daerah Gosowong, Kabupaten Halmahera Utara, Provinsi Maluku Utara
D aerah penelitian terletak pada area “Xâ€, Daerah Gosowong, Kabupaten Halmahera Utara, Provinsi Maluku Utara. Penelitian ini bertujuan untuk mengkarakterisasi sistem endapan porfiri meliputi litologi host rock, zona alterasi yang berkembang dan mineralisasi serta paragenesa mineral bijih. Metode yang digunakan dalam penelitian ini adalah pemetaan geologi pada Pit “A†dan core logging pada titik bor GM02 dan titik bor GM03. Hasil penelitian ini didapatkan tiga tipe intrusi diorit yaitu Diorit 1 (Coarse Hornblende Diorite), Diorit 2 (Medium Horblende-Quartz Diorite), Diorit 3 (Fine Hornblende Diorite) yang menerobos batuan vulkanik dan dasit. Zona alterasi yang berkembang pada daerah penelitian adalah zona alterasi biotit – kuarsa – magnetit ± anhidrit, zona alterasi serisit – kuarsa ± mineral lempung, dan zona alterasi klorit – epidot ± karbonat ± aktinolit ± mineral lempung. Proses alterasi pada daerah penelitian menunjukan adanya indikasi overprinting dimana zona alterasi biotit – kuarsa – magnetit ± anhidrit ter-overprint oleh zona alterasi serisit – kuarsa ± mineral lempung dan selanjutnya zona alterasi klorit – epidot ± karbonat ± aktinolit ± mineral lempung. Mineralisasi yang terdapat pada daerah penelitian terdiri atas mineral sulfida dan oksida diantaranya adalah magnetit, kalkopirit, bornit, kovelit, pirit, sfalerit, molibdenit, dan malakit. Intrusi diorit 2 (Medium Hornblende-Quartz Diorite) diinterpretasikan merupakan litologi host rock sebagai causative intrusion mineralisasi pada daerah penelitian.
T he research area is located in \"X\" area, Gosowong District, North Halmahera Regency, North Maluku Province. This study aims to characterize porphyry deposit systems including host rock lithology, alteration zones that develop, mineralization and ore mineral paragenesis. The method used in this research is geological mapping at Pit \"A\" and core logging at drill hole GM02 and drill hole GM03. The results of this study showed three types of diorite intrusion, namely Diorite 1 (Coarse Hornblende Diorite), Diorite 2 (Medium Horblende-Quartz Diorite), Diorite 3 (Fine Hornblende Diorite) which intruded through volcanic and dacite rocks. Alteration zones that develop in the study area are biotite – quartz – magnetite ± anhydrite alteration zones, sericite – quartz ± clay mineral alteration zones, and chlorite – epidote ± carbonate ± actinolite ± clay mineral alteration zones. The alteration process in the study area shows indications of overprinting where the biotite – quartz – magnetite ± anhydrite alteration zone is overprinted by the sericite – quartz ± clay mineral alteration zone and later the chlorite – epidote ± carbonate ± actinolite ± clay mineral alteration zone. The mineralization in the study area consists of sulfide and oxide minerals including magnetite, chalcopyrite, bornite, covellite, pyrite, sphalerite, molybdenite and malachite. Diorite 2 intrusion (Medium Hornblende-Quartz Diorite) is interpreted as a host rock lithology as a causative intrusion mineralization in the study area.