| Experimental Study on the Solubility of Cr^2 in Olivine,Orthopyroxene and Spinel Solid Solutions |
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| 摘 要： | Experiments have been performed on the system MgO-SiO2-Cr-O at 0-2.88 GPa and 1100-1450℃,focusing on the stability of Cr^2 in olivine(O1),orthopyroxene(Opx) and spinel(Sp) and its partitioning between these phases.Analytical reagent grade chemicals,MgO,SiO2,Cr2O3.and Cr were used to make starting mixtures.Excess Cr(50%) was then added in these mixtures to ensure that the resultant phases were in equilibrium with the metal Cr.Flux of BaO B2O3(%) was added for facilitating experimental equilibrium and crystal growth.Cr was used as capsule material.All phases in the product were identified by X-ray and analyzed by electron microprobe,The contents of CrO in the different phases(O1,Opx and Sp)were calculated according to stoichiometry.The obtained results of calculation indicate that Cr^3 in Ol and Opx is negligible.The experimental results show;(a) with increasing temperature and decreasing pressure,Cr^2 solubility in Ol,Opx and Sp increases;(b) with in creasing temperature,the partitioning coefficient of Mg and Cr^2 between Ol and Opx decreases,that between Opx and Sp increases,and that between Ol and Sp remains almost unchanged;(c) the effect of pressure on all partitioning coefficients is negligible.
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| 关 键 词： | 铬离子 可溶性 橄榄石 尖晶石 化学反应 |
Experimental study on the solubility of Cr2+ in olivine, orthopyroxene and spinel solid solutions |
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| Authors: | Li Jianping Hugh St C O’Neill Friedrich Seifert |
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| Institution: | (1) Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou;(2) Bayerisches Geoinstitut, Universitat Bayreuth, D-95440 Bayreuth, Germany |
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| Abstract: | Experiments have been performed on the system MgO-SiO2-Cr-O at 0–2.88 GPa and 1100–1450°C, focusing on the stability of Cr2+ in olivine (Ol), orthopyroxene (Opx) and spinel (Sp) and its partitioning between these phases. Analytical reagent grade
chemicals, MgO, SiO2, Cr2O3, and Cr were used to make starting mixtures. Excess Cr (50%) was then added in these mixtures to ensure that the resultant
phases were in equilibrium with the metal Cr. Flux of BaO + B2O3 (%) was added for facilitating experimental equilibrium and crystal growth. Cr was used as capsule material. All phases in
the product were identified by X-ray and analyzed by electron microprobe. The contents of CrO in the different phases (Ol,
Opx and Sp) were calculated according to stoichiometry. The obtained results of calculation indicate that Cr3+ in Ol and Opx is negligible. The experimental results show: (a) with increasing temperature and decreasing pressure, Cr2+ solubility in Ol, Opx and Sp increases; (b) with increasing temperature, the partitioning coefficient of Mg and Cr2+ between Ol and Opx decreases, that between Opx and Sp increases, and that between Ol and Sp remains almost unchanged; (c)
the effect of pressure on all partitioning coefficients is negligible. |
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| Keywords: | Cr2+ solubility olivine orthopyroxene spinel experimental study |
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