Zinc partitioning between mantle minerals and basaltic melts: Application to revisit the Zn/FeT redox proxy
文献类型：期刊论文
| 作者 | Sun, Zhongxing1,2,3; Gao, Mingdi2; Xiong, Xiaolin1,2 |
| 刊名 | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| 出版日期 | 2024-11-15 |
| 卷号 | 385页码:141-155 |
| 关键词 | Zn partitioning Melt Zn/Fe-T ratio Mantle fO(2) |
| ISSN号 | 0016-7037 |
| DOI | 10.1016/j.gca.2024.09.010 |
| 英文摘要 | Zn/Fe-T (Fe-T=Fe2+ + Fe3+) ratios in primitive melts have been proposed as a redox proxy to assess the redox states of the upper mantle. However, to effectively use the melt Zn/Fe-T ratio as a redox proxy, it is necessary to compare variations of melt Zn/Fe-T ratios induced by changes in oxygen fugacity (fO(2)) with variations due to changes in Zn-Fe contents and mineralogy of the sources. Here we show that the melt Zn/Fe-T ratio variation caused by fO(2) change can be expressed as Delta(Zn-m/FemT) = (Zn-per/Fe-per(T))* Delta(Fe-m(2+)/Fe-m(T))/(D-Zn(per/m)/D-Fe(2+per/m)). Zn/Fe-T ratios in most arc and MORB peridotites (Zn-per/Fe-per(T)) are 9.0 +/- 1.0*10(-4), and melt Fe2+/Fe-T ratio variation resulted from fO(2) change [Delta(Fe-m(2+)/Fe-m(T))] can be easily obtained by the existing model. Hence, if the Zn and Fe2+ partition coefficients (D-Zn(per/m) and D-Fe(2+per/m)) between melt and peridotite are known, the melt Zn/Fe-T ratio variation resulting from fO(2) change can be estimated. In this study, we determined D-Zn between olivine, orthopyroxene, clinopyroxene and basaltic melts at 0.75-2.5 GPa and 1250-1450 degrees C. Our data show that melt composition (expressed as MgO content) dominantly controls the mineral-melt Zn partitioning under peridotite melting conditions. These data, along with published mineral-melt D-Fe(2+) data, enable us to calculate appropriate D-Zn(per/m)/D-Fe(2+per/m), which is 0.78 +/- 0.02 under arc and MORB spinel peridotite melting conditions. Based on these parameters, the calculated average melt Zn/Fe-T ratio variation caused by per log unity fO(2) change in typical fO(2) span of arc and MORB mantles is only similar to 0.69 +/- 0.20*10(-4). Alternatively, melt Zn/Fe-T ratio variations caused by changes in Zn-Fe contents and mineralogy of peridotites are +/- 1.10*10(-4). These findings indicate that melt Zn/Fe-T ratio variation induced by one log units fO(2) change is on the same order of magnitude as those caused by changes in Zn-Fe contents and mineralogy of peridotites. Therefore, unless the precise chemical and mineralogical compositions of the mantle sources can be determined independently, the melt Zn/Fe-T redox proxy is unsuitable for tracing the mantle fO(2). Our study, combined with recent works on melt Cu and V/Sc redox proxies, suggests that these redox proxies, previously considered as the strongest evidence for a reduced arc mantle, might not support the idea of a reduced arc mantle. |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:001346460600001 |
| 源URL | [http://ir.gig.ac.cn/handle/344008/82052]  |
| 专题 | 同位素地球化学国家重点实验室 |
| 通讯作者 | Sun, Zhongxing |
| 作者单位 | 1.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Beijing, Peoples R China 2.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Peoples R China 3.CAS Ctr Excellence Deep Earth Sci, Guangzhou 510640, Peoples R China |
| 推荐引用方式 GB/T 7714 | Sun, Zhongxing,Gao, Mingdi,Xiong, Xiaolin. Zinc partitioning between mantle minerals and basaltic melts: Application to revisit the Zn/FeT redox proxy[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2024,385:141-155. |
| APA | Sun, Zhongxing,Gao, Mingdi,&Xiong, Xiaolin.(2024).Zinc partitioning between mantle minerals and basaltic melts: Application to revisit the Zn/FeT redox proxy.GEOCHIMICA ET COSMOCHIMICA ACTA,385,141-155. |
| MLA | Sun, Zhongxing,et al."Zinc partitioning between mantle minerals and basaltic melts: Application to revisit the Zn/FeT redox proxy".GEOCHIMICA ET COSMOCHIMICA ACTA 385(2024):141-155. |
入库方式： OAI收割
来源：广州地球化学研究所
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