Инд. авторы:	Shatskiy A.F., Bekhtenova A.E, Arefiev A.V., Podborodnikov I.V., Vinogradova Y.G., Rezvukhin D.I., Litasov K.D.
Заглавие:	Solidus and melting of carbonated phlogopite peridotite at 3-6.5 GPa: Implications for mantle metasomatism
Библ. ссылка:	Shatskiy A.F., Bekhtenova A.E, Arefiev A.V., Podborodnikov I.V., Vinogradova Y.G., Rezvukhin D.I., Litasov K.D. Solidus and melting of carbonated phlogopite peridotite at 3-6.5 GPa: Implications for mantle metasomatism // Gondwana Research. - 2022. - Vol.101. - P.156-174. - ISSN 1342-937X. - EISSN 1878-0571.
Внешние системы:	DOI: 10.1016/j.gr.2021.07.023; WoS: 000702840000003;
Реферат:	eng: It is well known that water significantly lowers mantle solidi. But it turns out this paradigm is not always true. Here, we studied the interaction of K-rich carbonate melts with the natural garnet lherzolite from the Udachnaya kimberlite (Russia) in the presence of water at 3.0-6.5 GPa, corresponding to depths of 100-200 km. We found that at <= 1100 degrees C, the metasomatic interaction consumes garnet, orthopyroxene, and melt to produce phlogopite +/- K-richterite + magnesite +/- dolomite. Besides, primary clinopyroxene is replaced by one with a lower amount of jadeite component. Thus, the addition of water to the K-rich carbonate melt, infiltrating the subcontinental lithospheric mantle, should yield its partial or complete disappearance accompanied by phlogopitization and carbonation. The studied systems have H2O/K2O = 2, like that in phlogopite, and therefore correspond to carbonated phlogopite peridotite under fluid-absent conditions. At 4.0-6.5 GPa, the solidus of carbonated phlogopite peridotite is controlled by the following reaction: phlogopite + clinopyroxene + magnesite = garnet + o rthopyroxene + olivine + hydrous K-carbonatite melt, which is bracketed between 1100 and 1200 degrees C. At 3 GPa, the solidus temperature decreases to about 1050 degrees C presumably owing to the Ca-Mg exchange reaction, clinopyroxene + magnesite = orthopyroxene + dolomite, which stabilizes dolomite reacting with phlogopite at a lower temperature than magnesite. Our results suggest that the phlogopite- and carbonate-rich metasomatic vein networks, weakening rigid lithosphere and promoting continental rifting, could be formed as a result of infiltration of hydrous K-carbonatite melt at the base of subcontinental lithospheric mantle. Stretching and thinning of the cratonic lithosphere make geotherms warmer and shifts their intersections with the solidus of carbonated phlogopite peridotite to shallower depths. Consequently, the successive erosion of the continental lithosphere and ascent of the lithosphere-asthenosphere boundary during continental rifting should be accompanied by remelting of phlogopite-carbonate metasomes, upward percolation of K-rich melt, and its solidification at the front of the magmatic-metasomatic mantle system. (C) 2021 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
Ключевые слова:	PHASE-RELATIONS; C-O-H; UDACHNAYA-EAST KIMBERLITE; FLUID INCLUSIONS; XENOLITHS; SYSTEM K2CO3-MGCO3; MINERAL ASSEMBLAGES; GARNET PERIDOTITES; Earth's mantle; High-pressure experiment; Peridotite-CO2-H2O; Mantle metasomatism; Mantle partial melting; Phlogopite; Magnesite; K-richterite; Solidus carbonated phlogopite peridotite; HIGH-PRESSURE; DIAMOND FORMATION;
Издано:	2022
Физ. характеристика:	с.156-174