RARE-EARTH MINERALS IN CARBONADO FROM YAK UTIAN DIAMOND DEPOSITS

One carbonado from Yakutian deposits is analyzed using analytical tran smission electron microscopy (selected area electron diffraction and e nergy dispersive X-ray analysis). The carbonado contains rare-earth mi neral inclusions: a complex florencite mineral (substitutional solid s olution of florencite with isostructural minerals), xenotime-zircon in tergrowths, and substitutional solid solutions. The rare-earth inclusi ons are likely to reflect different stages of the geological history o f carbonade. The xenotime-zircon is indicative of high temperatures an d pressures of carbonade formation. The florencite is an indication of hydrothermal-metasomatic alteration of carbonade at lower P-T paramet ers.