KARAKTERISTIK ALTERASI SKARN DAN DISTRIBUSI MINERAL SULFIDA PEMBAWA TEMBAGA DI TAMBANG BIG GOSSAN LEVEL 2860L-2940L FOOTWALL WEST, PAPUA, INDONESIA: CHARACTERISTICS OF SKARN ALTERATION AND SULPHIDE MINERAL BEARING COPPER DISTRIBUTION AT BIG GOSSAN MINE 2860L-2940L FOOTWALL WEST, PAPUA, INDONESIA - Amalina, Nur; Meirawaty, Mira; Sonbait, Daniel; Burhannudinnur, Muhammad; Hafiz, Surya Darma; Rendy; Koesmawardani, Wildan Tri; Wijaya, Budi (Universitas Trisakti, 2025)
Tambang Big Gossan di Papua Tengah dikenal dengan mineralisasi tembaga yang terbentuk akibat intrusi diorit pada batuan karbonatan Formasi Waripi. Penelitian ini bertujuan menganalisis karakteristik alterasi dan mineralisasi tembaga di level 2860, 2900, dan 2940 Footwall West. Metode yang digunakan termasuk pemetaan geologi dan analisis laboratorium (petrografi, mineragrafi, dan XRD). Hasilnya, ditemukan empat satuan litologi serta lima zona alterasi, yaitu klinopiroksen-garnet-kuarsa, epidot-klorit-kuarsa-kalsit, garnet-kuarsa-kalsit-piro pilit-epidot, piropilit-kuarsa-kalsit, dan aktinolit-kuarsa-klorit. Mineral sulfida tembaga utama adalah kalkopirit dan bornit, dengan pirit, pyrrhotite, dan magnetit sebagai mineral pembawa besi. Tembaga terakumulasi pada zona retrograde alterasi 2, 3, 4, dan 5. The Big Gossan mine in Central Papua is known for its copper mineralization, formed due to diorite intrusion into the carbonate rocks of the Waripi Formation. This study aims to analyze the characteristics of alteration and copper mineralization at levels 2860, 2900, and 2940 Footwall West. The methods used include geological mapping and laboratory analyses (petrography, mineragraphy, and XRD). The results revealed four lithological units and five alteration zones: clinopyroxene-garnet-quartz, epidote-chlorite-quartz-calcite, garnet-quartz-calcite-pyrophyllite-epidote, pyrophyllite-quartz-calcite, and actinolite-quartz-chlorite. The main copper sulfide minerals are chalcopyrite and bornite, with pyrite, pyrrhotite, and magnetite as iron-bearing minerals. Copper is concentrated in the retrograde alteration zones 2, 3, 4, and 5.