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Melt and fluid inclusions from volcanic quartz phenocrysts in the Shila gold / base metal ore district, Peru: precursors to ore‐forming epithermal solutions?
Author(s) -
Grancea Luminita,
AndréMayer AnneSylvie,
Cuney Michel,
Leroy Jacques L.
Publication year - 2002
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1046/j.1365-3121.2002.00435.x
Subject(s) - phenocryst , fluid inclusions , geology , geochemistry , melt inclusions , base metal , quartz , hydrothermal circulation , volcano , mineralization (soil science) , inclusion (mineral) , chalcedony , mineralogy , volcanic rock , calcite , metallurgy , materials science , paleontology , welding , seismology , soil science , soil water
Despite the close association with volcanic activity, the source of metals and ligands in the epithermal ore deposits is still controversial. In order to explore the magmatic–hydrothermal connection further, silicate melt, saline‐ and water‐rich fluids, and CO 2 vapours are documented that are trapped as inclusions in quartz phenocrysts from dacitic dykes associated with epithermal gold/base metal mineralization in the Shila district (Peru). Melt inclusion characteristics, and microthermometric and laser Raman fluid inclusion data are presented. The investigation of melt and fluid inclusions reveals that the volatile phase of magmas might represent the precursors to the early chlorine‐rich ore‐forming epithermal solutions. Microthermometric investigations in magmatic quartz crystals and data on quartz mineralized veins suggest that the fluid evolution and ore deposition may be the result of several processes including: release of an evolving magmatic fluid, and/or boiling, and/or mixing.