The integration of physical rock properties, mineralogy and geochemistry for the exploration of large zinc silicate deposits: A case study of the Vazante zinc deposits, Minas Gerais, Brazil

The Proterozoic Vazante Hypogene Zinc Silicate District, Minas Gerais, Brazil: A Review of the Ore System Applied to Mineral Exploration

“…This major structure is clearly envisaged by the responses of the high gradient signal in its first vertical derivative of the anomalous magnetic field (Figure 7, modified from Baia [7] and McGladrey, [34]). The fault was interpreted as an early syn-sedimentary growth fault that underwent multiple reactivations during the Brasiliano Orogeny, including reverse faulting during compression that later evolved into a normal, sinistral fault during the orogenic event [4,13,24].…”

“…In the Vazante district, these structures are oriented mainly NE and may represent reactivation of basement or syn-sedimentary structures. This derivative product enhances patterns that define the structures that control the mineralization (modified from Baia [7] and McGladrey, [34]) (SG = Serra do Garrote; SPV = Serra do Poço Verde).…”

“…The onset of hematite precipitation commonly preceded the formation of willemite, and both minerals continued to precipitate during the main ore stage (Figure 8b) along with minor franklinite, zincite and rare smithsonite. The abundance of franklinite increases with proximity to mafic dikes [3]. The mafic dikes are hydrothermally altered and contain minor Zn-chlorite, sphalerite, and franklinite.…”

“…It is not clear if this scarcity of deposits is because the processes related to their genesis are uncommon, or because most of the exploration programs worldwide are targeting sulfide-rich systems. Furthermore, due to the specific physical rock properties of hypogene sulfide ore (e.g., McGladrey et al [3]), traditional Furthermore, due to the specific physical rock properties of hypogene sulfide ore (e.g., McGladrey et al [3]), traditional geophysical methods applied to the exploration of sulfide deposits have not been very successful in finding zinc silicate deposits.…”

“…Most papers on the ore system of the Vazante district have focused on the structural controls, alteration, ore mineralogy and geochemistry of specific deposits or occurrences [5,6,8,10]. There have also been some contributions on fluid evolution in the basin [9] and variations in the physical rock properties due to mineralization [3]. Several Proterozoic and Paleozoic carbonate sequences around the world have experienced a similar evolution to the Vazante Group, and these sequences could potentially host similar types of mineralization.…”