engleski

The ore-forming fluids in the Idria mercury mine, Slovenia

Idrija ore deposit is composed of epigenetic, hydrothermal, vein and disseminated mineralisation in the Upper Paleozoic and Lower Triassic sediments and syngenetic, sedimentary- exhalative Middle Triassic ore beds. It has almost monomineralic paragenesis, with the major mineral, cinnabar and rare pyrite, marcasite and metacinnabar. The fluid inclusion study revealed epithermal character of fluids (Th, 160-220°C), low to moderate salinity, between 2.6 and 12.8 wt % equ. NaCl, and CaCl2- NaCl-H2O composition, with narrow range of NaCl/CaCl2 ratios between 0.57 and 1.53. Laser Raman spectroscopy determined solid phases within inclusions as dolomite and cinnabar. Bulk ion compositions of fluids trapped in FIs were analyzed by ion chromatographic analysis. The fluids resemble, in their characteristics, to those within hydrothermal minerals in Triassic pillow lavas, formed by extrusion of basalts in the sea water.

SEDEX ore deposit; fluid inclusion; mercury; cinnabar

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