Chemistry of hydrothermal minerals as an exploration tool in Cu-Au-Mo porphyry type deposits. Examples from the Altar Project, San Juan

Abstract

Mineral chemistry studies on hydrothermal minerals have demonstrated their potential to significantly extend the geochemical footprint dimensions of porphyry-type deposits on the weakly altered rocks surrounding these large hydrothermal systems. Studies carried out in the Altar Central (AC) and Quebrada de la Mina (QDM) deposits of the Altar project (San Juan) allowed to recognize compositional variations in phyllosilicates and clays through electron microprobe studies, X-ray diffraction and spectroscopy infrared (SWIR) analysis, as well as in sulphides and quartz by means of electron microprobe analysis and LA-ICPMS. In this contribution, a summary review of the most significant compositional differences recognized in hydrothermal minerals from Altar project is provided as well as new preliminary data on investigations that are still being developed, which have the potential to be used in mineral exploration of Cu-Au-Mo porphyry type deposits and associated Au-Ag-Cu epithermal deposits.