High-Ba mica in olivinites of the Guli massif (Maimecha-Kotui province, Siberia)

High-Ba (similar to 11 wt.% BaO) phlogopite was found for the first time in olivinites of the Guli intrusion in the Maimecha-Kotui province of ultrabasic alkaline rocks and carbonatites. The high-Ba mica occurs in assemblage with a paragenesis of olivinite minerals-clinopyroxene, titanomagnetite, apatite, and ilmenite. High-Ba mica is an early phlogopite generation. Its magmatic crystallization led to a decrease in Ba content. Low-Ba mica is a late phlogopite generation. The high Ba/K ratios at the early stages of evolution of a mantle magmatic system are necessary for the formation of high-Ba minerals and point to magma formation at great depths and the contribution of mantle metasomatism to the geochemical characteristics of parental magmas. (C) 2012, V. S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B. V. All rights reserved.