North Range low-sulfide mineralization is dominantly hosted by Sudbury breccia, with amphibole-plagioclase equilibrium metamorphic temperatures of 440 to 533 ± 75oC, produced by the SICs thermal aureole. Mineralization led to increases in the bulk halogen content of the host Sudbury breccia and the formation of Ni-enriched ferromagnesian silicates. South Range low-sulfide mineralization is typically hosted by metabasalts of the Huronian Supergroup. Garnet-biotite-plagioclase-quartz geothermobarometry produced equilibrium metamorphic conditions of 513 to 645 ± 50oC and 2.0 to 7.7 ± 1.0 kbar, probably corresponding to a late-Penokean overprint of peak Blezardian/Penokean metamorphism. Silicates associated with South Range mineralization are compositionally similar to the host rock equivalents and no alteration selvage is commonly observed due to subsequent recrystallization. Platinum-group minerals (PGM) from the North Range comprise platinum and palladium tellurides and bismuth-tellurides, with Sb-bearing palladium bismuth-tellurides and sperrylite from the South Range. Kotulskite-sobolevskite from the North Range shows a previously unreported Ag-Pd substitution, with michenerite from irregular veinlet style mineralization showing the substitution of Se and Sb for Bi. Two unknown PGMs were identified from the South Range, along with kotulskite-sobolevskite-sudburyite crystals displaying extensive Te-Bi-Sb solid-solution not noted before at Sudbury. A new Se-bearing variant of pilsenite was identified at McKim. Polyphase aggregates from both Ranges indicate that Bi-Te melts may have been widespread at some stage postdating the emplacement of the main magmatic sulfides. Normalized plots for low-sulfide mineralization show enrichments in the precious and semimetals relative to contact and sharp-walled vein mineralization. This enrichment has resulted in elevated concentrations of Ag and Se in chalcopyrite and Pd+Ag and Se in pentlandite from the North Range. The mass balance for North Range samples found that a significant fraction of Ag and Se occurs in sulfides with all other elements preferring discrete phases. A substantial fraction of Pd is hosted by pentlandite on the South Range, with gersdorffite also a major host despite its low abundance. The enrichments observed reflect the formation of low-sulfide mineralization from a fractionated sulfide liquid and hydrothermal fluids that have interacted with a fractionated sulfide source, and suggest that the precious and semimetals behave incompatibly with crystallizing sulfide.

North Range low-sulfide mineralization is dominantly hosted by Sudbury breccia, with amphibole-plagioclase equilibrium metamorphic temperatures of 440 to 533 ± 75oC, produced by the SICs thermal aureole. Mineralization led to increases in the bulk halogen content of the host Sudbury breccia and the formation of Ni-enriched ferromagnesian silicates. South Range low-sulfide mineralization is typically hosted by metabasalts of the Huronian Supergroup. Garnet-biotite-plagioclase-quartz geothermobarometry produced equilibrium metamorphic conditions of 513 to 645 ± 50oC and 2.0 to 7.7 ± 1.0 kbar, probably corresponding to a late-Penokean overprint of peak Blezardian/Penokean metamorphism. Silicates associated with South Range mineralization are compositionally similar to the host rock equivalents and no alteration selvage is commonly observed due to subsequent recrystallization. Platinum-group minerals (PGM) from the North Range comprise platinum and palladium tellurides and bismuth-tellurides, with Sb-bearing palladium bismuth-tellurides and sperrylite from the South Range. Kotulskite-sobolevskite from the North Range shows a previously unreported Ag-Pd substitution, with michenerite from irregular veinlet style mineralization showing the substitution of Se and Sb for Bi. Two unknown PGMs were identified from the South Range, along with kotulskite-sobolevskite-sudburyite crystals displaying extensive Te-Bi-Sb solid-solution not noted before at Sudbury. A new Se-bearing variant of pilsenite was identified at McKim. Polyphase aggregates from both Ranges indicate that Bi-Te melts may have been widespread at some stage postdating the emplacement of the main magmatic sulfides. Normalized plots for low-sulfide mineralization show enrichments in the precious and semimetals relative to contact and sharp-walled vein mineralization. This enrichment has resulted in elevated concentrations of Ag and Se in chalcopyrite and Pd+Ag and Se in pentlandite from the North Range. The mass balance for North Range samples found that a significant fraction of Ag and Se occurs in sulfides with all other elements preferring discrete phases. A substantial fraction of Pd is hosted by pentlandite on the South Range, with gersdorffite also a major host despite its low abundance. The enrichments observed reflect the formation of low-sulfide mineralization from a fractionated sulfide liquid and hydrothermal fluids that have interacted with a fractionated sulfide source, and suggest that the precious and semimetals behave incompatibly with crystallizing sulfide.

Le massif de Tropoja est le plus septentrional des massifs de la ceinture orientale des ophiolites d'Albanie dont les caractères pétrologiques et métallogéniques s'apparentent aux produits magmatiques des arcs insulaires immatures. Quatre niveaux enrichis en chromite ont été définis d'après leur stratigraphie, leur structure et leur composition : trois dans le manteau et un dans les cumulats. D'importantes variations de la fugacité en oxygène ont accompagné la formation des chromitites et des minéralisations en élement du groupe du platine qui leur sont associées. Au Sud du massif, une forte fugacité en oxygène couplée à une faible fugacité en soufre seraient responsables de la précipitation, directement à partir du magma, d'alliages de fer et de platine, qui forment la minéralisation platinifère caractéristiques des cumulas de Tropoja. Cette minéralisation, rare dans les autres massifs ophiolitiques, est située dans un niveau bréchique, à l'interface de dunites basales et de pyroxénites. Les teneurs de platine, qui peuvent atteindre 11 grammes par tonne, sont corrélées positivement aux concentrations de chrome. Trois stades minéralisants y ont été définis, le dernier étant lié à des interactions entre minéraux et fluides tardifs. D'autres caractéristiques minéralogiques de cette minéralisation, importantes pour le traitement des minerais, ont été obtenues grâce à une étude statistique. Au Nord du massif, les minéralisations platinifères, localisées dans le manteau, sont associées à des sulfures de métaux de base.