• journal_title：The Canadian Mineralogist
• Contributor：Cǎlin G. Tămaş ; Laurent Bailly ; Lucreţia Ghergari ; Gary O’Connor ; Adrian Minuţ
• Publisher：Mineralogical Association of Canada
• Date：2006-
• Format：text/html
• Language：en
• Identifier：10.2113/gscanmin.44.2.367
• journal_abbrev：Can Mineral
• issn：0008-4476
• volume：44
• issue：2
• firstpage：367
• section：Articles

New investigations by optical microscopy, scanning electron microscopy (SEM) and electron-probe micro-analysis (EPMA) have been performed on samples of silver-rich, gold-poor veins from the Roşia Montană ore deposit, South Apuseni Mountains, in Romania. Common base-metal sulfides and sulfosalts consist of galena, Fe-poor sphalerite, argentiferous tetrahedrite, alabandite, pyrite and marcasite. They are intimately associated with abundant tellurides, among which hessite, altaite, sylvanite, petzite and cervelleite. An alloy of Au–Ag is subordinate, and mainly observed as micro-inclusions in hessite. A Te-rich argyrodite with a mean composition close to Ag_8.04Ge_0.90Te_2.07S_3.77 was also identified in one of the veins investigated. The Ge content of sphalerite and tetrahedrite is below the detection limit (~400 ppm). The dilemma concerning the presence or absence of tellurides in the Roşia Montană deposit is now solved; most of the ore deposits of the South Apuseni Mountains have a Te-rich signature. These results, combined with previous observations in the field and mineralogical and microthermometric studies, suggest that ore deposition at the Roşia Montană deposit evolved from an early Au-(Ag) low-sulfidation character to a late Ag–Te–(Ge–Au) intermediate-sulfidation character, and may be correlated with late magmatic pulses.