Record details

Title
    Gold-tourmaline assemblage in a Witwatersrand-like gold deposit, Ouro Fino, Quadrilátero Ferrífero of Minas Gerais, Brazil: the composition of gold and metallogenic implications
Author
    Brunetto, Wilson
    Cabral, Alexandre
    Koglin, Nikola
    Vymazalová, Anna
Language
    anglicky
Publication type
    článek v periodiku
Source title - serial
    Neues Jahrbuch für Mineralogie. Abhandlungen
Vol./nr.
    Roč. 189, č. 3
Pages
    11
Year
    2012
Thesaurus term
    gold, tourmaline, mercury, Ouro Fino, Moeda Formation, Quadrilátero Ferrífero
Keyword
    Assemblage
    Brazil
    Composition
    Deposit
    Ferrífero
    Fino
    Gerais
    Gold
    Gold-tourmaline
    Implications
    Metallogenic
    Minas
    Ouro
    Quadrilátero
    Witwatersrand-like
Abstract (in english)
   Ouro Fino, a Witwatersrand-like gold deposit in the Moeda Formation of the Minas Supergroup, Quadrilátero Ferrífero of Minas Gerais, Brazil, has visible gold lacking coeval sulfi de minerals. The visible gold is characteristically intergrown with tourmaline. The gold-tourmaline aggregates truncate sub- to euhedral pyrite, which is epigenetic because it occurs as overgrowths on rounded pyrite that is regarded as detrital. Hence the gold is hydrothermal in origin. Compositionally, the gold is argentiferous, with mercury contents between about 2 and 6 wt.%. Palladium and platinum are insignifi cant (1 ?g/g) in the gold. The mercury component in the gold and the gold-tourmaline assemblage suggest precipitation from boron-rich brines poor in sulfi de sulfur. In the metallogenic context of the Quadrilátero Ferrífero, the gold-tourmaline assemblage of the Moeda Formation can be understood as a reducing equivalent of the mercury-bearing, sulfi de-poor hydrothermal overprint on relatively more
   oxidised rocks of the overlying Itabira Group.
Contributor
    Česká geologická služba
Contributor code
    ČGS (RIV)
Source format
    R
Import date
    15. 10. 2014