Elemental Gains and Losses during Hydrothermal Alteration in Awak Mas Gold Deposit, Sulawesi Island, Indonesia: Constraints from Balanced Mineral Reactions

Hydrothermal gold mineralization is commonly associated with metasomatic processes resulting from interaction of hostrock infiltrating hot aqueous fluids. Understanding the alteration mechanism requires quantification element changes in altered rock, relative to unaltered or least-altered representing protolith. Balanced mineral reactions are used gain quantitative insight into process at Awak Mas deposit. Three representative samples were carefully selected pyllite and two zones bordering mineralization. Mineral mode, textural features, compositions studied by microscopy electron microprobe analyzer (EMPA). Quantitative modal analysis was performed a Quanta 650 F QEMSCAN® system. The hydrothermal sequence around starts proximal albite–ankerite–pyrite zone via distal albite–chlorite phyllite wall-rock. reaction calculations evaluate elemental gains losses. Most noticeable addition Si, Na Ca each zone. This represented almost complete replacement muscovite albite. Fe S highest Alteration least involved mass increase 14.5% neglectable volume 0.6%. 40.5% 0.47%, respectively. very low change during also corroborated preservation indicating isovolumetric reactions. albite may have had an important effect on rock failure mode ductile brittle, consequences for focusing fluid flow.