Baddeleyite segregations in zircon of the Azov zirconium-rare-earth deposit (Ukrainian Shield)

Baddeleyite as inclusions in zircon crystals is described for the first time from the ore zone of the Azov zirconium-rare-earth deposit in the Volodarsky (Pivdennokalchytsky) syenite Massif in the Ukrainian Shield. The main admixture in the zircon containing baddeleyite is hafnium (0.68 wt%). The baddeleyite occurs in a substance that fills cracks and that probably corresponds to glass. The chemical compositions of four baddeleyite segregations, and of the hosting glass, are presented. The baddeleyite formed as a result of interaction between zircon and silicate melt with a low SiO₂ content. The silicate melt formed under the influence of highthermobaric CO₂-fluid flows on the rock.