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Wüstite stability in the presence of a CO2-fluid and a carbonate-silicate melt : Implications for the graphite/diamond formation and generation of Fe-rich mantle metasomatic agents. / Bataleva, Yuliya V.; Palyanov, Yuri N.; Sokol, Alexander G. и др.
в: Lithos, Том 244, 01.02.2016, стр. 20-29.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Wüstite stability in the presence of a CO2-fluid and a carbonate-silicate melt
T2 - Implications for the graphite/diamond formation and generation of Fe-rich mantle metasomatic agents
AU - Bataleva, Yuliya V.
AU - Palyanov, Yuri N.
AU - Sokol, Alexander G.
AU - Borzdov, Yuri M.
AU - Bayukov, Oleg A.
PY - 2016/2/1
Y1 - 2016/2/1
N2 - Experimental simulation of the interaction of wüstite with a CO2-rich fluid and a carbonate-silicate melt was performed using a multianvil high-pressure split-sphere apparatus in the FeO-MgO-CaO-SiO2-Al2O3-CO2 system at a pressure of 6.3GPa and temperatures in the range of 1150°C-1650°C and with run time of 20h. At relatively low temperatures, decarbonation reactions occur in the system to form iron-rich garnet (Alm75Prp17Grs8), magnesiowüstite (Mg#≤0.13), and CO2-rich fluid. Under these conditions, magnesiowüstite was found to be capable of partial reducing CO2 to C0 that leads to the formation of Fe3+-bearing magnesiowüstite, crystallization of magnetite and metastable graphite, and initial growth of diamond seeds. At T≥1450°C, an iron-rich carbonate-silicate melt (FeO~56wt.%, SiO2~12wt.%) forms in the system. Interaction between (Fe,Mg)O, SiO2, fluid and melt leads to oxidation of magnesiowüstite and crystallization of fayalite-magnetite spinel solid solution (1450°C) as well as to complete dissolution of magnesiowüstite in the carbonate-silicate melt (1550°C-1650°C). In the presence of both carbonate-silicate melt and CO2-rich fluid, dissolution (oxidation) of diamond and metastable graphite was found to occur. The study results demonstrate that under pressures of the lithospheric mantle in the presence of a CO2-rich fluid, wüstite/magnesiowüstite is stable only at relatively low temperatures when it is in the absolute excess relative to CO2-rich fluid. In this case, the redox reactions, which produce metastable graphite and diamond with concomitant partial oxidation of wüstite to magnetite, occur. Wüstite is unstable under high concentrations of a CO2-rich fluid as well as in the presence of a carbonate-silicate melt: it is either completely oxidized or dissolves in the melt or fluid phase, leading to the formation of Fe2+- and Fe3+-enriched carbonate-silicate melts, which are potential metasomatic agents in the lithospheric mantle.
AB - Experimental simulation of the interaction of wüstite with a CO2-rich fluid and a carbonate-silicate melt was performed using a multianvil high-pressure split-sphere apparatus in the FeO-MgO-CaO-SiO2-Al2O3-CO2 system at a pressure of 6.3GPa and temperatures in the range of 1150°C-1650°C and with run time of 20h. At relatively low temperatures, decarbonation reactions occur in the system to form iron-rich garnet (Alm75Prp17Grs8), magnesiowüstite (Mg#≤0.13), and CO2-rich fluid. Under these conditions, magnesiowüstite was found to be capable of partial reducing CO2 to C0 that leads to the formation of Fe3+-bearing magnesiowüstite, crystallization of magnetite and metastable graphite, and initial growth of diamond seeds. At T≥1450°C, an iron-rich carbonate-silicate melt (FeO~56wt.%, SiO2~12wt.%) forms in the system. Interaction between (Fe,Mg)O, SiO2, fluid and melt leads to oxidation of magnesiowüstite and crystallization of fayalite-magnetite spinel solid solution (1450°C) as well as to complete dissolution of magnesiowüstite in the carbonate-silicate melt (1550°C-1650°C). In the presence of both carbonate-silicate melt and CO2-rich fluid, dissolution (oxidation) of diamond and metastable graphite was found to occur. The study results demonstrate that under pressures of the lithospheric mantle in the presence of a CO2-rich fluid, wüstite/magnesiowüstite is stable only at relatively low temperatures when it is in the absolute excess relative to CO2-rich fluid. In this case, the redox reactions, which produce metastable graphite and diamond with concomitant partial oxidation of wüstite to magnetite, occur. Wüstite is unstable under high concentrations of a CO2-rich fluid as well as in the presence of a carbonate-silicate melt: it is either completely oxidized or dissolves in the melt or fluid phase, leading to the formation of Fe2+- and Fe3+-enriched carbonate-silicate melts, which are potential metasomatic agents in the lithospheric mantle.
KW - Carbonate-silicate melt
KW - CO-fluid
KW - Decarbonation
KW - Graphite formation
KW - HPHT experiment
KW - Wüstite
UR - http://www.scopus.com/inward/record.url?scp=84950997869&partnerID=8YFLogxK
U2 - 10.1016/j.lithos.2015.12.001
DO - 10.1016/j.lithos.2015.12.001
M3 - Article
AN - SCOPUS:84950997869
VL - 244
SP - 20
EP - 29
JO - Lithos
JF - Lithos
SN - 0024-4937
ER -
ID: 25725769