Magnetite separates from the Shaquanzi Fe-Cu deposit in the eastern Tianshan are used for Re-Os geochronological study.Re-Os data show that magnetite separates contain ca.0.7 to 50.9 ppb Re and ca.16 to 63 ppt Os.Eigh...Magnetite separates from the Shaquanzi Fe-Cu deposit in the eastern Tianshan are used for Re-Os geochronological study.Re-Os data show that magnetite separates contain ca.0.7 to 50.9 ppb Re and ca.16 to 63 ppt Os.Eight samples yield a model 3isochron age of(303±12)Ma(2),which is within uncertainty consistent with of the Re-Os date(295±7 Ma)of associated pyrite.Tectonic evolution shows that the Late Carboniferous Aqishan-Yamansu belt was a back-arc rift.Therefore,the Re-Os age of ca.300 Ma indicates that the Shaquanzi Fe-Cu deposit may have formed in a back-arc extensional environment and was closely related to mantle-derived magmatism.The successful application of Re-Os magnetite geochronology in the Shaquanzi Fe-Cu deposit suggests that the purity of magnetite,relatively high Re and Os contents,and the closure of Re-Os systematic are base factors for a successful Re-Os geochronology.There would be a good prospect for Re-Os geochronology for magnetite.展开更多
基金financially supported by the National Basic Research Program of China(Grant No.2012CB416804)the ‘‘CAS Hundred Talents’’ Project from the Chinese Academy of Sciences(Grant No.KZCX2-YW-BR-09)to Qi Liang
文摘Magnetite separates from the Shaquanzi Fe-Cu deposit in the eastern Tianshan are used for Re-Os geochronological study.Re-Os data show that magnetite separates contain ca.0.7 to 50.9 ppb Re and ca.16 to 63 ppt Os.Eight samples yield a model 3isochron age of(303±12)Ma(2),which is within uncertainty consistent with of the Re-Os date(295±7 Ma)of associated pyrite.Tectonic evolution shows that the Late Carboniferous Aqishan-Yamansu belt was a back-arc rift.Therefore,the Re-Os age of ca.300 Ma indicates that the Shaquanzi Fe-Cu deposit may have formed in a back-arc extensional environment and was closely related to mantle-derived magmatism.The successful application of Re-Os magnetite geochronology in the Shaquanzi Fe-Cu deposit suggests that the purity of magnetite,relatively high Re and Os contents,and the closure of Re-Os systematic are base factors for a successful Re-Os geochronology.There would be a good prospect for Re-Os geochronology for magnetite.
