| DOI: | 10.1038/ngeo2028
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| 论文题名: | Copper enrichment in arc magmas controlled by overriding plate thickness |
| 作者: | Chiaradia M.
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| 刊名: | Nature Geoscience
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| ISSN: | 17520894
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| 出版年: | 2014
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| 卷: | 7, 期:1 | | 起始页码: | 43
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| 结束页码: | 46
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| 语种: | 英语
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| 英文摘要: | Porphyry copper systems supply about 75% of the world's copper. They form above subduction zones and are preferentially associated with calc-alkaline magmas. Such magmas result from continuous iron depletion during differentiation, in contrast to tholeiitic magmas that show initial iron enrichment during differentiation. The formation of calc-alkaline magmas is favoured by high water content and oxygen fugacity. These characteristics, as well as magmatic metal contents, are thought to be imparted in the mantle source by fluids of the subducted slab. Yet this process does not explain why porphyry copper systems preferentially occur in thicker arcs. Here I present a statistical assessment of more than 40,000 published geochemical analyses of magmatic rocks from 23 Quaternary-aged volcanic arcs worldwide. I find that magmas of thicker arcs are systematically more calc-alkaline and more depleted in copper than magmas of thinner arcs. This implies that the missing copper in the former accumulates as copper sulphides within or at the base of thicker arcs. Such copper accumulations are an essential step in forming porphyry systems. These results suggest that the thickness of the overriding plate provides a more important control on magma differentiation than the composition of the mantle source, and can explain the preferential association of porphyry copper systems with calc-alkaline magmas and thicker arcs. © 2014 Macmillan Publishers Limited. |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/106439
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| Appears in Collections: | 气候减缓与适应
科学计划与规划
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作者单位: | Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, Geneva 1205, Switzerland
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| Recommended Citation: | |
Chiaradia M.. Copper enrichment in arc magmas controlled by overriding plate thickness[J]. Nature Geoscience,2014-01-01,7(1)
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