First find of srilankite in the Urals

摘要

The first find of srilankite (very rare Zr and Ti oxide, Ti2ZrO6) in the Urals and the third find in Russia is reported. Srilankite forms very small (0.5-20 mu m) inclusions in some rutile grains. These minerals are observed in the rare rock variety, corundum-bearing spinel-saphirine hornblendite forming a block in serpentinized amphibolizied peridotite of the Ilmeny-Vishnevogorsk Complex, near the village of Taiginka, Chelyabinsk oblast. Srilankite has not been observed in such an association yet. The composition of the host rock provides evidence for its deep (the lowermost crust of the Earth) origin. Srilankites of the Urals are distinguished from all others by the high concentrations of UO2, ThO2, HfO2, and Nb2O5, which provides additional evidence for their crustal origin. Srilankite may indicate high-temperature and high-pressure conditions of rock formation.