Buru island, metamorphic rocks, gold deposit, epithermal.
Abstract
An investigation on gold occurrence in Buru island is needed to determine type of deposit in the area. This study aims to analyse mineralisation, alteration and metamorphic facies of metamorphic-hosted gold deposit in Buru area by using petrographic method, x-ray flourescense, x-ray diffraction, and polish section. The results reveral that there are two types of metamorphic rocks: schists and phyllite. Greenschist facies are charecterized by muscovite mineral, quartz, chlorite, biotite, clay mineral, and codierite. Phyllite is in the same genetic condition with schist (medium metamorphism), with formation temperature ranges from 300°C to 450°C with a pressure around 1-8 Kbar through a regional metamorphism process. Alteration in quartz veins indicated the nature of proximal zone to ore zone. Silicic alteration (quartz) is also found intensely, and it is generally associated by propylitic alteration (chlorite) and sericitic (muscovite). Mineralisation follows the direction of the distribution of quartz veins with crustiform banding texture. The quartz vein thickness is from 40 cm to 50 cm. The alteration and mineralisation occurrence of the studied area suggests epithermal gold deposits type.
