Affiliation:
1. D.S. Korzhinskii Institute of Experimental Mineralogy of the RAS
Abstract
Influence of the supercritical C-O-H-fluid (7.5 wt.%) onto melting phase relations of the multicomponent multiphase diamond-forming system olivine-jadeite-diopside-(Mg-Fe-Ca-Na-carbonates)-(C-O-H) in experiments at 6 GPa and 700–1200 °C (the upper mantle conditions) has been studied. The peritectic reaction of olivine and jadeite-bearing melt with garnet formation has been retained as a key mechanism of the ultrabasic-basic evolution of diamond-forming melts. The CO2-fluid and silicate components react forming carbonate phases. The H2O-fluid together with carbonates has essentially lowered temperatures of the liquidus and solidus boundaries. The phase of supercritical water fluid and water-bearing carbonate nesquehonite (Nes) MgCO3·3H2O were identified with the Raman-spectroscopy method after crystallization of the completely mixed silicate-carbonate-(C-O-H-fluid) melt.
Publisher
The Russian Academy of Sciences
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