Caracterização da geometria de zonas de alteração hidrotermal - Estudo de caso no deposito aurifero de Brumal, Quadrilatero Ferrifero, Minas Gerais

TL;DRAbstract

The Brumal gold deposit is located in the northeastem portion of the Quadrilatero Ferrífero region.It is enclosed within an Archaean volcano-sedimentary sequence (i.e., Nova Lima Group ).Regional host rocks comprise two distinct greenstone assemblages, from bottom to top: (i) mafic to ultramafic volcanics and (ii) clastic and chemical sediments.At least two phases of deformation affected these rocks.These two phases were coaxial and probably evolved under a single deformation event associated to compression towards WNW.The gold mineralization is intrinsically associated to banded iron fomations (B!Fs ), which are usually constrained within carbonaceous-rich schists at both hangingwall and footwall.The ore bodies contain a wealth of sulphides but especially arseoopyrite.Gold occurs mostly as inclusions in arseoopyrite.The development of sulphide-rich B!Fs involved the percolation of mineralizing fluids through structural traps, triggering the sulphidation ofiron carbonates and magnetite

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