Diffusion-driven chromium isotope fractionation in ultramafic cumulate minerals Elemental and isotopic evidence from the Stillwater Complex
文献类型：期刊论文
| 作者 | Bai, Yang; Su, Ben-Xun; Xiao, Yan; Chen, Chen; Cui, Meng-Meng; He, Xiao-Qing; Qin, Li-Ping; Charlier, Bernard |
| 刊名 | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| 出版日期 | 2019-10-15 |
| 卷号 | 263页码:167-181 |
| ISSN号 | 0016-7037 |
| DOI | 10.1016/j.gca.2019.07.052 |
| 英文摘要 | To investigate chromium diffusion kinetics in ultramafic cumulate minerals, we analyzed the Cr elemental and isotopic compositions of olivine, orthopyroxene, and chromite from the Stillwater layered intrusion. Core-to-rim compositional profiles reveal that Cr elemental concentrations decrease from 60 to 20 ppm in olivine and from 5000-4600 to 2700-2400 ppm in orthopyroxene. These zoned Cr distributions in olivine and orthopyroxene suggest that Cr was lost by diffusion into the melt. Olivine and orthopyroxene have delta Cr-53 values ranging from -0.09 to 0.25 parts per thousand and from -0.11 to 0.07 parts per thousand, respectively, higher than the values of coexisting chromite (-0.23 to -0.07 parts per thousand). This isotopic disequilibrium can be explained by diffusion-driven kinetic fractionation during cooling. The preferential diffusion of light Cr isotopes from silicate minerals to the melt resulted in isotopically heavier olivine and orthopyroxene, but the kinetic diffusion between chromite and melt negligibly affected the isotopic compositions of chromite grains due to their high Cr concentrations. Modeling results based on the observed Cr contents and isotopic compositions of silicate minerals constrain the cooling time of the Peridotite Zone in the Stillwater magmatic system to have been 10-100 kyr. (C) 2019 Elsevier Ltd. All rights reserved. |
| 源URL | [http://ir.isl.ac.cn/handle/363002/34039]  |
| 专题 | 青海盐湖研究所_盐湖地质与环境实验室 中国科学院青海盐湖研究所 |
| 推荐引用方式 GB/T 7714 | Bai, Yang,Su, Ben-Xun,Xiao, Yan,et al. Diffusion-driven chromium isotope fractionation in ultramafic cumulate minerals Elemental and isotopic evidence from the Stillwater Complex[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2019,263:167-181. |
| APA | Bai, Yang.,Su, Ben-Xun.,Xiao, Yan.,Chen, Chen.,Cui, Meng-Meng.,...&Charlier, Bernard.(2019).Diffusion-driven chromium isotope fractionation in ultramafic cumulate minerals Elemental and isotopic evidence from the Stillwater Complex.GEOCHIMICA ET COSMOCHIMICA ACTA,263,167-181. |
| MLA | Bai, Yang,et al."Diffusion-driven chromium isotope fractionation in ultramafic cumulate minerals Elemental and isotopic evidence from the Stillwater Complex".GEOCHIMICA ET COSMOCHIMICA ACTA 263(2019):167-181. |
入库方式： OAI收割
来源：青海盐湖研究所
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