Dimitrova, DA; Iliev, TH; Mladenova, VG
Pyrite is formed in all mineral assemblages described in the Martinovo and Chiprovtsi deposits. It is observed as euhedral, cubic to cubic-octahedral, coarse- to fine-grained crystals and spherulitic aggregates. Pyrite associates with molybdenite and scheelite in the retrograde skarn assemblage; with arsenopyrite and lollingite in the later postskarn assemblage; with galena, sphalerite, chalcopyrite, tennantite-tetrahedrite and Ag-Sb sulfosalts in the polymetallic assemblage and with chalcopyrite, tetrahedrite-tennantite, galena and cinnabar in the low temperature assemblage. In all assemblages pyrite is enriched in As. Arsenic contents vary in a wide range - from <0.10 wt. % up to 4.78 wt. %. Pyrite from the retrograde skarn assemblage show enrichment in Ti, Co, Zr, Y, La, Ce, Dy, Yb, Th, U, Bi and Pb. Gold has concentrations between 0.90 and 1.93 ppm. Pyrite from the polymetallic assemblage is enriched in Cu, Zn, Ag, Pb, As and Sb. Spherulitic pyrite is enriched in Co, Ni, Zn, Se, Ag, Sb, Pb, TI and Hg. Chemical composition of pyrite of different mineral assemblages from the Martinovo and Chiprovtsi deposit reflect the gradual change of the elemental composition of the ore-forming fluids in the area.