인도네시아 파찌딴 광화대 함 금속 광체의 안정동위원소 특성

Abstract

주요어 : 동-아연-연-금, 스카른, 열수 , 망상광체, 맥상광체, 안정동위원소, 파찌딴 광화대, 인도네시아 Extensive base-metal and/or gold bearing ore mineralizations occur in the Pacitan mineralized district of the south western portions in the East Java, Indonesia. Metallic ore bodies in the Pacitan mineralized district are classified into two major types: 1) skarn type replacement ore bodies, 2) fissure filling hydrothermal ore bodies. Skarn type replacement ore bodies are developed typically along bedding planes of limestone as wall rock around the quartz porphyry and are composed mineralogically of skarn minerals, magnetite, and base metal sulfides. Hydrothermal ore bodies differ mineralogically in relation to distance from the quartz porphyry as source igneous rock. Hydrothermal ore bodies in the district are porphyry style Cu-Zn-bearing stockworks as proximal ore mineralization and Pb-Zn(-Au)-bearing fissure filling hydrothermal veins as distal ore mineralization. Sulfur isotope compositions in the sulfides from skarn and hydrothermal ore bodies range from 6.7 to 8.2‰ and from 0.1 to 7.9‰, respectively. The calculated δ 34 S values of H2S in skarn-forming and hydrothermal fluids are 0.9 to 7.1‰ (5.6-7.1‰ for skarn-hosted sulfides and 0.9-6.8‰ for sulfides from hydrothermal deposits). The change from skarn to hydrothermal mineralization would have resulted in increased SO4/H2S ratios and corresponding decreases in δ 34 S values of H2S. The calculated δ 18 O water values are: skarn magnetite,