Hg-Tl-bearing manganese oxide from Conta Historia manganese deposit, Quadrilatero Ferrifero, Minas Gerais, Brazil

摘要

In the Quadrilatero Ferrifero, the world-class iron district of Minas Gerais, Brazil, numerous manganese oxide deposits occur in the Palaeoproterozoic Itabira Iron Formation (Itabira Group). Although some deposits have been investigated, ~(5,23,24,25,31,33,36,41,42) systematic geochemical studies are lacking. Reconnaissance geochemical data on the manganese ore of the Conta Historia manganese oxide deposit, which are presented here, indicate important contents of mercury, thallium, barium and strontium (Table 1), suggesting an event of hydrothermal manganese oxide mineralization in the Quadrilatero Ferrifero that has hitherto gone unrecognized owing to the deep weathering imprint.