Depicting the 3D geometry of ore bodies using implicit lithological modeling: An example from the horto-baratinha iron deposit, guanhães block, MG

Abstract

The definition of geological domains is essential for mineral exploration and is traditionally done manually, section by section, in a laborious, time consuming and subjective process, to construct a 3D model. The technique referred to as implicit modeling is an option to model deposits in a fast and practical manner. This article presents the lithological model of the Horto-Baratinha iron deposit, located in the Antônio Dias municipality, central-eastern part of Minas Gerais state, constructed using the Leapfrog Geo® software. The deposit is situated at the Guanhães tectonic block that is a basement domain of the Neoproterozoic Araçuaí Orogenic Belt. The deposit is comprised of itabirite-hosted high-grade iron bodies (>60 wt.% Fe) associated with polydeformed mica schists, amphibole schist with a Statherian maximum deposition age, enclosed by Statherian granitoids of the Borrachudos Suite and cross-cut by undeformed pegmatite dikes crystallized during Late Ediacaran-Cambrian. The sequence was affected by progressive multiple deformation phases, associated with the collisional stage of the Brasiliano Orogeny (630-560 Ma), generating a dome and basin mesoscale refolding shape. The model points the proximity between high-grade bodies and pegmatite indicating the possibility that the intrusions contribute to the iron mineralization.