Evaluation of the potential for Ni-Cu-PGE sulfide deposits associated with komatiites in Brazil.
Komatiite, Ni-Cu-PGE sulfide, greenstone belt, Brazil
This research aims to evaluate the Brazilian potential for Ni-Cu-PGE sulfide deposits associated with komatiites. This is done primarily by studying known deposits such as Fortaleza de Minas and Boa Vista de Crixás. Understand their particularities and metallogenetic processes inherent to these deposits, and then compare them with other komatiites in non-mineralized Brazil. All this with the main objective of answering the question “Is there any geological/petrological justification for the scarcity of Ni-Cu-EGP sulfide deposits associated with Brazilian komatiites?” For that, an integrated approach of qualitative and quantitative data from geology, lithogeochemistry, S and Sm-Nd isotopic geochemistry, and mineral chemistry was carried out. The results obtained so far indicate that the Boa Vista deposit follows the standard metallogenetic model, associated with basal contact with another more fractionated basaltic sequence, in a channeled flow volcanic environment, associated with olivine cumulus. The source of sulfur is external, most likely from carbonaceous phyllite. There is a set of isotopic and geochemical data of trace elements that point to intense crustal contamination and post-magmatic remobilization of some chemical elements.