HIGH-Ba MICA IN OLIVINITES OF THE GULI MASSIF ( Maimecha-Kotui province, Siberia )
L.N. Kogarkoa, I.D. Ryabchikovb, and D.V. Kuz'minc,d
aVernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, ul. Kosygina 19, Moscow, 119991, Russia
bInstitute of Ore Deposit Geology, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences, Staromonetnyi per. 35, Moscow, 119017, Russia
cMax Planck Institut fur Chemie, 27 Joh.-Joachim-Becher-Weg, Mainz, 55128, Germany
dV.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
Keywords: Ba-phlogopite, Guli intrusion, olivinite, mantle metasomatism
Pages: 1209-1215
Subsection: PETROLOGY, GEOCHEMISTRY, AND MINERALOGY
Abstract
High-Ba (~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.
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