GEOCHEMICAL FEATURES OF QUARTZ SYENITE-POROPHYRES OF THE OLEKMINSK STOCK FROM THE CHARA-SINSK DYKE SWARM, YAKUTSK-VILYUI LARGE IGNEOUS PROVINCE

The new geochemical data on rare and rare earth elements and their interpretation together with those previously published for syenite-porphyries of the Olekminsk stock of the Chara-Sinsk dyke swarm of the Vilyui paleorift will be present in the report. The features of the felsic rocks formation, their belonging to the magmatism of the Yakutsk-Vilyui large igneous province will be show. A mixture of indicators of the different sources has been established for quartz syenite porphyries: both depleted mantle (plume) and oceanic island basalts (OIB). Probably the presence of garnet in the source. Also, products of low degrees of melting of crustal substrates under the influence of the heat of the main magma could have participated in the formation of quartz syenite porphyries. The crustal material here could be garnet-bearing rocks of the basement of the Siberian craton of granulite facies metamorphism. It is assumed, the parent mantle-derived magma has been subjected to substantial crustal contamination as a one of mechanism of differentiation.