Palladogermanide PdGe2 from Sulfidized Anorthosite of the Yoko-Dovyren Intrusion: First Finding in Russia

Resumo

The Yoko-Dovyren ultramafic–mafic layered intrusion includes the Baikal deposit of Cu–Ni sulfide ores with Pt–Pd mineralization in the bottom part, and “horizons” and pockets of low-sulfide ores with Pt–Pd mineralization at the upper levels of the section. The highest concentration of Pd, Pt, Au, Ag, Hg, and Cd, as well as the widest variability in the noble-metal minerals, is typical of the vein-like bodies of anorthosite and pegmatoid anorthosite in the upper part of the critical horizon at the boundary between troctolite and the overlying gabbronorite. Most of the noble-metal minerals are the postmagmatic pneumatolytic (fluid–metasomatic) phases. Among them are palladogermanide with 19.8 wt % Ge, paolovite with 8.1% Ge, and zvyagintsevite with 0.55% Ge. The composition of palladogermanide is Pd_2.03(Ge_0.80As_0.15Bi_0.02)_0.97; Ge is significantly replaced with As in this phase, which is typical of endogenic Ge minerals.