| Инд. авторы: | Podborodnikov I.V., Shatskiy A., Arefiev A.V., Chanyshev A.D., Litasov K.D. |
| Заглавие: | The system Na2CO3-MgCO3 at 3GPa |
| Библ. ссылка: | Podborodnikov I.V., Shatskiy A., Arefiev A.V., Chanyshev A.D., Litasov K.D. The system Na2CO3-MgCO3 at 3GPa // High Pressure Research. - 2018. - Vol.38. - Iss. 3. - P.281-292. - ISSN 0895-7959. - EISSN 1477-2299. |
| Внешние системы: | DOI: 10.1080/08957959.2018.1488972; SCOPUS: 2-s2.0-85048760254; WoS: 000438637800008; |
| Реферат: | eng: It was suggested that Na-Mg carbonates might play a substantial role in mantle metasomatic processes through lowering melting temperatures of mantle peridotites. Taking into account that natrite, Na2CO3, eitelite, Na2Mg(CO3)(2), and magnesite, MgCO3, have been recently reported from xenoliths of shallow mantle (110-115km) origin, we performed experiments on phase relations in the system Na2CO3-MgCO3 at 3GPa and 800-1250 degrees C. We found that the subsolidus assemblages comprise the stability fields of Na-carbonate+eitelite and eitelite+magnesite with the transition boundary at 50mol% Na2CO3. The Na-carbonate-eitelite eutectic was established at 900 degrees C and 69mol% Na2CO3. Eitelite melts incongruently to magnesite and a liquid containing about 55mol% Na2CO3 at 925 +/- 25 degrees C. At 1050 degrees C, the liquid, coexisting with Na-carbonate, contains 86-88mol% Na2CO3. Melting point of Na2CO3 was established at 1175 +/- 25 degrees C. The Na2CO3 content in the liquid coexisting with magnesite decreases to 31mol% as temperature increases to 1250 degrees C. According to our data, the Na- and Mg-rich carbonate melt, which is more alkaline than eitelite, can be stable at the P-T conditions of the shallow lithospheric mantle with thermal gradient of 45mW/m(2) corresponding to temperature of 900 degrees C at 3GPa.
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| Ключевые слова: | eitelite; Raman; shallow mantle; carbonatite; 6 GPA; PHASE-RELATIONS; DEEP MANTLE; CARBONATED ECLOGITE; LITHOSPHERIC MANTLE; HIGH-PRESSURE; PERIDOTITE; SOLIDUS; ALKALI; Na2CO3-MgCO3; DIAMOND; |
| Издано: | 2018 |
| Физ. характеристика: | с.281-292 |