| Инд. авторы: | Litasov K.D., Ohtani E. |
| Заглавие: | Phase relations in the peridotite-carbonate-chloride system at 7.0-16.5 GPa and the role of chlorides in the origin of kimberlite and diamond |
| Библ. ссылка: | Litasov K.D., Ohtani E. Phase relations in the peridotite-carbonate-chloride system at 7.0-16.5 GPa and the role of chlorides in the origin of kimberlite and diamond // Chemical Geology. - 2009. - Vol.262. - Iss. 1-2. - P.29-41. - ISSN 0009-2541. - EISSN 1878-5999. |
| Внешние системы: | DOI: 10.1016/j.chemgeo.2008.12.027; SCOPUS: 2-s2.0-70349832320; |
| Реферат: | eng: Melting phase relations have been determined in a model chloride-carbonate-bearing peridotite at 7.0-16.5 GPa and 1200-1800 °C. The typical assemblage coexisting with partial melts is forsterite/wadsleyite-enstatite/clinoenstatite-garnet. In contrast to carbonated peridotite, clinopyroxene was absent in chloride-carbonate system. Also, carbonatite melt formed at low-degree of partial melting are enriched by CaO. We observed Ca-and Mg-bearing carbonatite melts in all experiments. The solidus temperature was estimated using the stability of magnesite and appearance of alkali-poor carbonatite melt at 1300 °C at 10.5 GPa and 1400 °C at 16.5 GPa. Halides are stable 100-200° C above this 'apparent' solidus. This fact indicates that melt composition in chloride-carbonate peridotite can be effectively controlled by the presence of water. In the anhydrous environments a low-fraction of 'dry' Cl-and alkali-poor Ca-Mg-rich carbonatite melts can be formed and migrate from the source, whereas under the hydrous conditions, chloride can be dissolved into water to form alkali-rich chloride-carbonate brine-like liquids. At higher temperatures (1400-1600 °C) two immiscible carbonatite and chloride-carbonate liquids may coexist. The composition of carbonatite and chloride-carbonate melts is consistent with that of melt inclusions in fibrous/cloudy diamonds worldwide. Typical trends of melt evolution upon cooling and formation the melts included in diamonds may involve formation of immiscible Si-poor carbonatite and Si-poor chloride-carbonate melts from homogenous Clbearing kimberlite-or carbonatite-like melt. Published by Elsevier B.V.
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| Ключевые слова: | Chloride; Diamond; High pressure experiment; Kimberlite; Mantle; Peridotite; Chloride; High pressure experiment; temperature effect; pressure effect; peridotite; partial melting; melt inclusion; mantle; magnesite; kimberlite; high pressure; diamond; chloride; carbonatite; carbonate; Chlorine compounds; Silicate minerals; Melting; Experiments; Diamonds; Diamond deposits; Carbonation; Bearings (structural); Peridotite; Mantle; Carbonate; Kimberlite; |
| Издано: | 2009 |
| Физ. характеристика: | с.29-41 |