2D Gravimetric Modelling of the Central Portion of Quadrilátero Ferrífero, Brazil

The Quadrilátero Ferrífero, located at the southern São Francisco craton, is one of the most important metallogenic districts in Brazil.Multiple deformational events affected this region and several studies, based mainly on structural field mapping argue about its tectonic evolution.Geophysical techniques applied to delineate subsurface can be useful for a better understanding of its tectonic framework.The present study consists of a gravimetric survey in the central portion of Quadrilátero Ferrífero, encompassing its three main geological units: the TTG basement, the Rio das Velhas greenstone belt, and the Minas Supergroup.The acquired data were processed in three gravimetric 2-D profiles and the modeling was based also on surface geological data and previous tectonic studies of the area.The geophysicalgeological profiles modeled suggest that the Rio das Velhas basin, in the Nova Lima-Caeté tectonostratigraphic block, shows distinct composition and thickness in its eastern and western regions.The eastern portion would be composed of a thin base layer with a predominance of mafic/ultramafic metavolcanic rocks and a thick top layer with metasedimentary rocks.On the other hand, the western area would have a remarkable predominance of mafic/ultramafic metavolcanic rocks belonging to a thick basal layer.For the Minas Supergroup in the Serra da Piedade region, an inverted syncline is the model that best suited the gravimetric data.The inverted flank is exposed by the Serra da Piedade and the normal flank doesn't outcrop.