Fluid Inclusions at the Plavica Au-Ag-Cu Telescoped Porphyry–Epithermal System, Former Yugoslavian Republic of Macedonia (FYROM)

Abstract

The Plavica Au-Ag-Cu porphyry and high sulfidation (HS) epithermal deposit is located at the Kratovo⁻Zlatovo volcanic field in Eastern Former Yugoslavian Republic of Macedonia. In this study, new fluid inclusions data provide additional evidence of the presence of a porphyry style mineralization which is associated with an overlain HS epithermal deposit. The Oligocene⁻Miocene magmatic rocks have a calc⁻alkaline to high-K calc⁻alkaline affinity and consist of sub-volcanic intrusions and volcanic rocks. Previous studies distinguished four alteration types: (a) Sericitic, (b) advanced argillic, (c) silicification, and (d) propylitic alteration. Fluid inclusions showed an early magmatic brine in porphyry style veins with high salinity (33⁻57 wt% NaCl equiv.), which coexists with a vapor rich fluid with lower salinity (14⁻20 wt% NaCl equiv.), at temperatures 380⁻500 °C, under boiling conditions. At shallower depths, the fluid inclusions demonstrate various HS⁻epithermal deposits which were formed by moderate to low salinity (3⁻14 wt% NaCl equiv.) hydrothermal fluids at lower temperatures from 200 to 300 °C.

Keywords

• Porphyry
• epithermal
• hypersaline fluid
• boiling
• Plavica