DOI: 10.1038/ngeo2651
论文题名: Porphyry copper enrichment linked to excess aluminium in plagioclase
作者: Williamson B.J. ; Herrington R.J. ; Morris A.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2016
卷: 9, 期: 3 起始页码: 237
结束页码: 241
语种: 英语
Scopus关键词: aluminum
; calc alkaline rock
; chemical composition
; copper
; enrichment
; igneous geochemistry
; magmatism
; melt
; plagioclase
; porphyry
; subduction zone
; Chile
英文摘要: Porphyry copper deposits provide around 75%, 50% and 20% of world copper, molybdenum and gold, respectively. The deposits are mainly centred on calc-alkaline porphyry magmatic systems in subduction zone settings. Although calc-alkaline magmas are relatively common, large porphyry copper deposits are extremely rare and increasingly difficult to discover. Here, we compile existing geochemical data for magmatic plagioclase, a dominant mineral in calc-alkaline rocks, from fertile (porphyry-associated) and barren magmatic systems worldwide, barren examples having no associated porphyry deposit. We show that plagioclase from fertile systems is distinct in containing 'excess'aluminium. This signature is clearly demonstrated in a case study carried out on plagioclase from the fertile La Paloma and Los Sulfatos copper porphyry systems in Chile. Further, the presence of concentric zones of high excess aluminium suggests its incorporation as a result of magmatic processes. As excess aluminium has been linked to high melt water contents, the concentric zones may record injections of hydrous fluid or fluid-rich melts into the sub-porphyry magma chamber. We propose that excess aluminium may exclude copper from plagioclase, so enriching the remaining melts. Furthermore, this chemical signature can be used as an exploration indicator for copper porphyry deposits. © 2016 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106057
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: University of Exeter - Camborne School of Mines, Penryn, Cornwall, United Kingdom; Department of Earth Sciences, Natural History Museum, Cromwell Road, London, United Kingdom
Recommended Citation:
Williamson B.J.,Herrington R.J.,Morris A.. Porphyry copper enrichment linked to excess aluminium in plagioclase[J]. Nature Geoscience,2016-01-01,9(3)