3D inversion of airborne gravity gradiometry data in mineral exploration: A case study in the Quadrilatero Ferrifero, Brazil

We present a case study of applying 3D inversion of gravity gradiometry data to iron ore exploration in Minas Gerais, Brazil. The ore bodies have a distinctly high-density contrast and produce well-defined anomalies in airborne gravity gradiometry data. We have carried out a study to apply 3D inversion to a 20 km(2) subarea of data from a larger survey to demonstrate the utility of such data and associated inversion algorithm in characterizing the deposit. We examine multiple density contrast models obtained by first inverting T-zz; then T-xz, T-yz, and T-zz jointly; and finally all five independent components to understand the information content in different data components. The commonly discussed T-zz component is sufficient to produce geologically reasonable and interpretable results, while including additional components involving horizontal derivatives increases the resolution of the recovered density model and improves the ore delineation. We show that gravity gradiometry data can be used to delineate the iron ore formation within this study area.