Occurrences of Pd–Pt Bismuthotellurides and a Phosphohedyphane-Like Phase in Sulfide Veins of the Monchepluton Layered Complex, Kola Peninsula, Russia

• Published in: Minerals
• Main Authors: Andrei Y. Barkov, Andrey A. Nikiforov, Larisa P. Barkova, Robert F. Martin
• Format: Text
• Language: English
• Published: Multidisciplinary Digital Publishing Institute 2022
• Subjects: pyromorphite–phosphohedyphane solid solution; chlorine; Cl-rich compounds; platinum-group minerals; massive sulfide veins; basic–ultrabasic complexes; layered intrusions; Fennoscandian Shield; Kola Peninsula; Russia; Fennoscandian; kola peninsula
• Online Access: https://doi.org/10.3390/min12050624

We describe occurrences of platinum-group minerals (PGM) and an uncommon mineral enriched in Cl, and provide a brief review of Cl-bearing minerals associated with basic–ultrabasic complexes. An unusual phosphohedyphane-like phase (~30 µm), close to CaPb4(PO4)3Cl, occurs in one of the PGM-bearing veins of massive sulfides in the Monchepluton layered complex, Kola Peninsula, Russia. These veins consist of varying amounts of pyrrhotite, pentlandite, chalcopyrite, pyrite and accessory grains of galena; they are fairly abundant in the heavy-mineral concentrate, as are small (<0.1 mm) grains of PGM: michenerite, sperrylite, Bi-enriched members of the merenskyite–moncheite series and kotulskite, also rich in Bi. The PGE mineralization is attributed to a low-temperature deposition at the hydrothermal stage. The pyromorphite–phosphohedyphane solid solution likely formed as a secondary phase under conditions of a progressive build-up of oxygen fugacity via oxidation reactions of a precursor grain of galena and involving Ca, as an incompatible component of the sulfides, in a medium of residual fluid enriched in Cl.