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Autori: Plotinskaya Olga Yu., Damian Floarea, Prokofiev Vsevolod Yu., Kovalenker Vladimir, Damian Gheorghe
Editorial: Carpathian Journal of Earth and Environmental Sciences, Vol. 4, No. 2, p.89-100, 2009.
Tellurides are significant minerals in gold deposits both as gold carriers and as indicators of PTx-conditions. In the Inner Carpathians belt tellurides are abundant in most deposits of the golden Quadrilateral (Apuseni Mountains) and sporadic in the Banska Stiavnica zone and the Zlata Bania zone. In the presenr paper we describe for first time altaite and tetradymite occurences in the Baia Mare district proved by e-probe data. Altaite (PbTe) was found in the Cavnic deposit in assemblage with sphalerite, galena, and rhodonite. It’s chemical composition is close to stoichiometric: Te 37.61 wt. % and Pb 60.51 wt. %, total 98.12 wt. %. In the Cu-Bi assemblage of the Nistru deposit occurs tetradymite (Bi2Te2S) in intergrowth with chalcopyrite, gustavite, and native Au. Tetradymite appears as very small grains with the composition Te 36.99 wt.%, Bi 61.93 wt.% S 4.55 wt.% and calculated formula Bi2.03Te1.99S0.98. Paratellurite (TeO2), found in assemblage with native gold and gustavite, forms intergrowth with a 2-microns phase containing Au and Te. Thermodynamic constrains supported by fluid inclusions data indicate that altaite formation at Cavnic was likely to be a result of temperature decrease from 300 to 250-200oC and fS2 drop. At Nistru tetradymite formation does not require temperature decrease and might be a result of fS2 drop and/or fTe2 increase.
Cuvinte cheie: Epithermal, Baia Mare, tellurides, altaite, tetradymite, fahlore, mineral assemblages, fluid inclusions.