宁强陨石中不透明矿物集合体的氧同位素和成因研究 |
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关键词:opaque assemblage O-isotope in situ ion microprobe analysis Ningqiang carbonacecus chondrite |
基金项目:本文为中国科学院百人计划“引进国外杰出人才”资助项目 |
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Oxygen Isotopes and Origin of Opaque Assemblages in Ningqiang Carbonaceous Chondrites |
Chondrules and matrix of the Ningqiang carbonaceous chondrite contain abundant opaque assemblages (OAs). They are composed of magnetite, Ni-rich metals and Fe-sulfides, with minor phosphate, silicate, and trace amounts of platinum-group element metals. The ion probe measurements show that; ①The O-isotopic compositions of magnetite fall on a mass-dependent fractionation line (slop:0.51±0.04, Δ17O:-2.8±0.4‰), and δ18O values range widely from -15.3‰ to-1.6‰. ②The OAs and chondrules (Δ17O of the olivine:-5.0‰) are unequilibrated with regard to their O-isotopic compositions. OAs most likely formed by secondary alteration processes in a parent body, where aqueous fluid oxidized the metal into magnetite and enriched the residual metal in Ni. |
WANG Ying,XU Weibiao,HUA Xin,GUAN Yunbin.2005.Oxygen Isotopes and Origin of Opaque Assemblages in Ningqiang Carbonaceous Chondrites[J].Acta Geoscientica Sinica,26(z1):6-9. |
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