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Release of gold-bearing fluids in convergent margin magmas prompted by magnetite crystallization

Citation

Sun, WD and Arculus, RJ and Kamenetsky, VS and Binns, RA, Release of gold-bearing fluids in convergent margin magmas prompted by magnetite crystallization, Nature, 431, (7011) pp. 975-978. ISSN 0028-0836 (2004) [Refereed Article]

DOI: doi:10.1038/nature02972

Abstract

A relationship between convergent margin magmas and copper-gold ore mineralization has long been recognized. The nature of the genetic link is controversial, particularly whether the link is due to high-oxygen-fugacity (fO2) melts and fluids released from subducted slabs or to brine exsolution during magmatic evolution. For submarine, subduction-related volcanic glasses from the eastern Manus basin, Papua New Guinea, we here report abrupt decreases in gold and copper abundances, coupled with a switch in the behaviour of titanium and iron from concentration increases to decreases as SiO 2 rises. We propose that the abrupt depletion in gold and copper results from concurrent sulphur reduction as a result of fO2 buffering, causing enhanced formation of copper-gold hydrosulphide complexes that become scavenged from crystallizing melts into cogenetic magmatic aqueous fluids. This process is particularly efficient in oxidized arc magmas with substantial sulphate. We infer that subsequent migration and cooling of exsolved aqueous fluids create links between copper-gold mineralization and arc magmatism in the Manus basin, and at convergent margins in general.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geochemistry
Research Field:Geochemistry not elsewhere classified
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Kamenetsky, VS (Professor Vadim Kamenetsky)
ID Code:32673
Year Published:2004
Web of Science® Times Cited:174
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2004-08-01
Last Modified:2007-10-23
Downloads:0

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