Xavier, Roberto P., Rusk, Brian, Emsbo, Poul, and Monteiro, Lena V.S. (2009) Composition and source of salinity of ore-bearing fluids in Cu-Au systems of the Carajás Mineral Province, Brazil. In: Proceedings of the 10th Biennial Meeting of the the SGA 2009 (1) pp. 272-274. From: 10th Biennial Meeting of the SGA 2009, 17-20 August 2009, Townsville, QLD, Australia.

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Abstract

The composition and Cl/Br – Na/Cl ratios of highly saline aqueous fluid inclusions from large tonnage (> 100 t) IOCG deposits (Sossego, Alvo 118, and Igarapé Bahia) and a Paleoproterozoic intrusion-related Cu-Au- (Mo-W-Bi-Sn) deposit (Breves; < 50 Mt)) in the Carajás Mineral Province have been analysed by LA-ICP-MS and ion chromatography. In both Cu-Au systems, brine inclusions are Ca-dominated (5 to 10 times more than in porphyry Cu-Au fluids), and contain percent level concentrations of Na and K. IOCG inclusion fluids, however, contain higher Sr, Ba, Pb, and Zn concentrations, but significantly less Bi, than inclusions from the intrusion-related Breves deposit. Cu is consistently below detection limits in brine inclusions from the IOCG and intrusion-related systems, with Fe not detected in the latter. Cl/Br and Na/Cl ratios of the IOCG inclusion fluids range from entirely evaporative brines (bittern fluids; e.g. Igarapé Bahia and Alvo 118) to values that indicate mixing with magma-derived brines. Cl/Br and Na/Cl ratios of the Breves inclusion fluids strongly suggest the involvement of magmatic brines, but possibly also incorporated bittern fluids. Collectively, these data demonstrate that residual evaporative and magmatic brines were important components of the fluid regime involved in the formation of Cu-Au systems in the Carajás Mineral Province.

Item ID:	11861
Item Type:	Conference Item (Abstract / Summary)
ISBN:	978-0-9805586-8-5
Keywords:	Carajás; iron oxide-copper-gold; fluid inclusions; LA-ICP-MS; halogens
Related URLs:	http://sga2009.jcu.edu.au/
Additional Information:	Conference theme "Smart Science for Exploration and Mining"
Date Deposited:	10 Sep 2010 01:13
FoR Codes:	04 EARTH SCIENCES > 0403 Geology > 040307 Ore Deposit Petrology @ 100%
SEO Codes:	84 MINERAL RESOURCES (excl. Energy Resources) > 8401 Mineral Exploration > 840102 Copper Ore Exploration @ 100%
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