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Palladian gold from the cauê iron mine, Itabira District, Minas Gerais, Brazil

Published online by Cambridge University Press:  05 July 2018

G. R. Olivo ,
M. Gauthier  and
M. Bardoux
G. R. Olivo
Affiliation:
Université du Québec à Montréal, Département des sciences de la terre, case postale 8888, succ. A, Montréal, PQ, Canada, H3C 3P8
M. Gauthier
Affiliation:
Université du Québec à Montréal, Département des sciences de la terre, case postale 8888, succ. A, Montréal, PQ, Canada, H3C 3P8
M. Bardoux
Affiliation:
Université du Québec à Montréal, Département des sciences de la terre, case postale 8888, succ. A, Montréal, PQ, Canada, H3C 3P8
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Abstract

Palladian gold from the Cauê iron mine, Itabira District, Minas Gerais, Brazil is found in horizons of hydrothermally-altered Lake Superior-type oxide-facies iron-formation locally called jacutinga. Palladium content of the gold grains varies from 1% to 20%, high palladium values being associated with palladium-copper-oxide inclusions and showing island-mainland and replacement (relict) textures in the Corpo Y and Corpo X orebodies. In the Aba Leste orebody, palladium is homogeneously distributed throughout the gold grains.

Palladium and gold mineralization was synchronous with intense D1 shearing. Palladium was deposited early during the generation of S1-mylonitic foliation, and was replaced by gold during progressive deformation.

At high oxygen fugacities (hematite stability field) and high temperatures (up to 600°C) Pd and Au may have been transported as chloride complexes, and their deposition may have occurred mainly as a result of changes in pH, but dilution of Cl concentrations may have also caused Pd and Au precipitation. Deposition of Pd as selenide may have taken place early during the creation of S1-fabrics.

Keywords

goldpalladiumItabira, Braziliron-formationjacutinga
Type
Mineralogy
Information
Mineralogical Magazine , Volume 58 , Issue 393 , December 1994 , pp. 579 - 587
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1994

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