气候变化领域集成服务门户(CCPortal): How to make porphyry copper deposits

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DOI	10.1016/j.epsl.2019.115868
	How to make porphyry copper deposits
	Lee C.-T.A.; Tang M.
发表日期	2020
ISSN	0012821X
卷号	529
英文摘要	Much of the world's economic copper resources are hosted in porphyry copper deposits (PCDs), shallow level magmatic intrusions associated mostly with thick (>45km) magmatic arcs, such as mature island arcs and continental arcs. However, a well-known, but unresolved paradox, is that arc magmas traversing thick crust, particularly in continental arcs, are generally depleted in Cu whereas in island arcs, where PCDs are less common, magmas become enriched in Cu. Here, we show that the formation of PCDs requires a complex sequence of intra-crustal magmatic processes, from the lower crust to the upper crust. PCDs form when the crust becomes thick (>45km) enough to crystallize garnet. Garnet fractionation depletes Fe from the magma, which drives sulfide segregation and removal of most of the magma's Cu into the lower crust, leaving only small amounts of Cu in the residual magma to make PCDs. However, because garnet is depleted in ferric iron, the remaining Fe in the magma becomes progressively oxidized, which eventually oxidizes sulfide to sulfate, thereby releasing sulfide bound Cu from the magma into solution. This auto-oxidation of the magma, made possible by deep-seated garnet fractionation, increases the ability of endogenic magmatic fluids to self-scavenge Cu from large volumes of otherwise Cu-poor magmas and then transport and concentrate Cu to the tops of magmatic bodies. Examination of the occurrence of PCDs in the central Andes shows that ore formation occurs when continental arcs reach their maximum thickness (>60km), just before the termination of magmatism. © 2019 Elsevier B.V.
关键词	andes andesite arc volcanism copper copper porphyry subduction zone
英文关键词	Copper; Deposits; Garnets; Iron; Segregation (metallography); Sulfur compounds; andes; andesite; Arc volcanism; Magmatic intrusions; Maximum thickness; Porphyry copper deposits; Subduction zones; Sulfide segregations; Copper deposits; andesite; copper; garnet; island arc; magma; ore deposit; porphyry; subduction zone; volcanism; Andes
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202719
作者单位	Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, United States
推荐引用方式 GB/T 7714	Lee C.-T.A.,Tang M.. How to make porphyry copper deposits[J],2020,529.
APA	Lee C.-T.A.,&Tang M..(2020).How to make porphyry copper deposits.Earth and Planetary Science Letters,529.
MLA	Lee C.-T.A.,et al."How to make porphyry copper deposits".Earth and Planetary Science Letters 529(2020).