| Diffusion-driven chromium isotope fractionation in ultramafic cumulate minerals Elemental and isotopic evidence from the Stillwater Complex | |
| Bai, Yang; Su, Ben-Xun; Xiao, Yan; Chen, Chen; Cui, Meng-Meng; He, Xiao-Qing; Qin, Li-Ping; Charlier, Bernard | |
| 2019-10-15 | |
| 发表期刊 | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| ISSN | 0016-7037 |
| 卷号 | 263页码:167-181 |
| 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. |
| DOI | 10.1016/j.gca.2019.07.052 |
| 引用统计 | |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.isl.ac.cn/handle/363002/34039 |
| 专题 | 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. |
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| Diffusion-driven chr（10081KB） | 期刊论文 | 出版稿 | 开放获取 | CC BY-NC-SA | 浏览 请求全文 | |
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