Sulfidic and non-sulfidic indium mineralization of the epithermal Au–Cu–Zn–Pb–Ag deposit San Roque (Provincia Rio Negro, SE Argentina) — with special reference to the “indium window” in zinc sulfide

Abstract At San Roque in Patagonia's Rio Negro Province, Argentina, an In–Au–Cu–Zn–Pb–Ag mineralization ( Salt–mud flats controlled the youngest mineralization with Mn, Li, Ca, Mg, V, Sr, Cu, Ag and In bound to oxides, hydroxides, sulfates and subordinate carbonates. The quartz vein mineralization is made up of oxides, hydroxides prevailing over sulfides and containing W, Fe, Au, As, Pb, In, and Cu. It formed at the passage from the vadose into the phreatic zones under oxidizing to slightly reducing conditions. The level marks the boiling level of the hydrothermal solutions involved in the mineralizing process. The hypogene stockwork mineralization is exclusively made up of sulfides containing Zn, Pb, Cu, In, Ag and Bi in the phreatic zones. It developed under reducing conditions. Indium is present at all levels within the volcanic rocks and has been derived from sphalerite rich in Cd (