Phosphate-bearing minerals in the advanced argillic alteration zones of high-sulphidation type ore deposits in the Carpatho-Pannonian Region
Reference:
Acta Mineralogica-Petrographica, Szeged 2004, Vol. 45/1, pp. 81–92
Szerző:
Bajnóczi Bernadett
Seres-Hartai Éva
Nagy Géza
Abstract:
Ca-dominant, Al-phosphate-sulphate (APS) minerals with minor Ba, Sr, K, Na and REE contents were found in hydrothermal alunite or separately in advanced argillic alteration zones associated with high-sulphidation type epithermal systems in Hungary (Velence Mountains) and Slovakia (Podpolom deposit, Klokoč). Electron microprobe analyses show that these APS minerals are woodhouseite with SO42- and PO43- molar ratio varying between 1:3 and 2:1.
The occurrence of APS minerals in close association with alunite and other hydrothermal minerals indicates a hypogene origin for these phases. Extensive leaching of magmatic minerals (apatite, feldspar) in the host rock by strongly acidic magmatic-hydrothermal fluids induced the formation of phosphate-bearing minerals. Changing physico-chemical characteristics of the hydrothermal fluids with time resulted in zoning and multiphase formation of these alunite-type minerals, with a common late phase dominated by pure sulphate (alunite). This is the first detailed documentation of hydrothermal APS minerals in alteration systems of the Carpatho-Pannonian region.
acta2004, advanced argillic alteration, Al-phosphate-sulphate mineral, alunite, Carpatho-Pannonian region, high-sulphidation, phosphate, Podpolom deposit, sulphate, Velence Mountains, woodhouseite
