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Gold in the Lousal mine, Iberian Pyrite Belt, Portugal
Orientador(es)
Resumo(s)
Recent exploration boreholes in the Lousal Mine, located within the Portuguese sector of the Iberian Pyrite Belt (IPB)
yielded marked concentrations in gold/electrum in a section of core consisting of banded metasediments with massive
pyrite. Preliminary research indicates that the gold is associated with native bismuth and bismuthinite and is clearly
late in the paragenetic sequence occurring in fine chalcopyrite (± covellite)-bismuthinite-gold filled veinlets within the
dominant and more massive pyrite. The pale yellow gold grains are fine, seldom reaching more than 6 ..m in length
and half of that in thickness. EPMA results indicate that silver concentrations in gold grains can be as high as 27
wt.%. The results show similarities with conclusions drawn from the IPB on the Spanish side where gold of Co-Bi
geochemical association is found as electrum with abundant to common Co and Bi minerals. These associated with
pyrite and/or chalcopyrite are characterized by an abundance of sedimentary facies and show that the gold
association formed at high temperature (>300 °C) during the initial phases of massive sulphide formation.
Descrição
Palavras-chave
Jazigos minerais Ouro Mina do Lousal (concelho de Grândola, Portugal) Faixa Piritosa Ibérica
Contexto Educativo
Citação
Oliveira, Daniel P. S. de... [et al.] - Gold in the Lousal mine, Iberian Pyrite Belt, Portugal. In: 11th SGA Biennial Meeting : Let's Talk Ore Deposits, Antofagasta, Chile, 26-29th September 2011, p. 757-759