Minerálna a geochemická charakterizácia premeny typu pokro?ilej argilitizácie na Au-porfyrovom lo?isku Biely vrch, Slovensko – vrty DVE-10 a DVE-51

摘要

The Biely vrch deposit is a new economic Au-porphyry mineralization discovered in Slovakia. The deposit is located in the central zone of the Neogene Javorie stratovolcano, situated in the eastern part of the Central Slovakian Volcanic Field. Au-porphyry deposits represent a relatively new type of deposits of the porphyry group that has a growing importance in the world. The Biely vrch deposit shares many properties typical for Au-porphyry deposits in general. Zones of advanced argillic alteration are the uppermost part of the porphyry system and the youngest alteration. They are spread from surface to depth of several hundred metres in the shape of ledges. The main clay mineral from studied samples was kaolinite. Its average amount was almost 33 wt %. That value was determined by XRD quantitative analyses of 13 bulk samples from the depth of 2 to 205 m. The amount of kaolinite was ranged from 3 to 54 wt % in the particular samples. Pyrophyllite attends the kaolinite as the second clay mineral in the upper part of advanced argillic alteration. Dickite, another index mineral of advanced argillic alteration, occurred with kaolinite more frequently than pyrophyllite but in smaller amount. Almost in half of the studied samples significant presence of illite was identified, part of them belong to intermediate argillic zone. Clay minerals were studied also by electron microscopy and IR spectroscopy. Quartz was determined as the main non-clay mineral. The first mineral quantitative analyses showed big potential to use a product of advanced argillic alteration as a secondary source of silicate raw material with high content of Al2O3. Models of distribution of selected elements were prepared simultaneously with mineralogical characterization. Several good correlations were observed of these distributions and alterations and their products.