NEPHELINE BEARING TYLAITES IN A DUNITE-CLINOPYROXENITE-GABBRO ASSOCIATION FROM THE PLATINUM BEARING BELT OF THE URALS

Abstract

Tylaites - feldspathic olivine clinopyroxenites from the Tagil'skiy dunite-clinopyroxenite massif in the platinum-bearing belt of the Urals - are of magmatic origin. They are composed of phenocrysts of zonal clinopyroxene, cemented by a fine-grained aggregate of olivine, clinopyroxene, biotite and magnetite, and also orthoclase-plagioclase and orthoclase-nepheline (pseudoleucitic) symplektites. The rocks represent hypabyssal facies of olivine clinopyroxenites, which indicates that the dunite-clinopyroxenite-gabbro formation in the platinum-bearing belt of the Urals belongs to a volcano-plutonic association.