Deep-seated magmas and their sources for the Maimecha-Kotui province (Polar Siberia): study of silicate melt inclusions in clinopyroxene

摘要

Alkali-ultrabasic carbonatite complexes are the derivates of the deepest mantle magmas. Problems of sources of their generation, features of melting and crystallization conditions are very complicate and interesting tasks for recent petrology. We used geochemical and thermobarogeochemical methods for considering of these problems. Basic-ultrabasic effusive rocks with different alkalinity (melanephelinites, trachydolerites and tholeiites) are the objects of this study. These rocks are widespread near the Krestovskii massif and situated around the intrusive body of olivinites, werhlites, pyroxenites, melilite and monticellite rocks. These volcanics form the series of lava flows together with trachybasalts, fragments of tholeiitic basalts, trachyandesite, basaltic tuffs and acidic tuffites. Dykes of alkali picrites, trachydolerites, trachybasalts and plagioclase porphyrites are localized on the contact of the intrusion with effusive strata.