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

摘要

We present a case study of applying 3D inversion of gravity gradiometry data to ironore 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 km2 subarea of data from a larger surveyto 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 Tzz component is sufficient to produce geologically reasonable and interpretable results, whileincluding additional components involving horizontal derivatives increases the resolutionof 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.