| Popis: |
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 Pd2.03(Ge0.80As0.15Bi0.02)0.97; Ge is significantly replaced with As in this phase, which is typical of endogenic Ge minerals. |
