GEOLOGIC-PETROGRAPHICAL CHARACTERISTIC OF MELILITE-BEARING ROCKS OF TURIY PENINSULA (KOLA PENINSULA)

摘要

Melilite-bearing rocks of Turiy peninsula have been studied from the point of their mineral parageneses and age relations. It is shown that these rocks are located in different zones inside separate massifs and there is a successive evolution of parageneses within transition from okaites (or melteigites) to turjaites. The detailed investigation of melilite has revealed variation of its chemical composition. Several generations of this mineral differing in composition have been detected in uncompagrites. Results of the study indicate heterogeneity and heterochronous origin of the series of melilite-bearing rocks. Okaites had been formed while the crystallization of Ca-rich alkaline melts and other members of the series were developed due to metasomatic replacement of okaites or ultramafic rocks.