Structurally constrained lithology characterization using magnetic and gravity gradient data over an iron ore formation

Abstract

It is often desirable to extract meaningful lithologic information directly from geophysical data. Here, we describe a multi-faceted approach that combines the known geologic sections of a site from borehole data with recovered density and magnetic susceptibility distributions from 3D inversion of airborne gravity gradient and magnetic data. The technique can produce end-member solutions based on average property values extracted from literature and well records; or, it can be implemented using the geologic sections to extract an appropriate range of property values to address the model smoothing common to modern 3D generalized inversions. To demonstrate our approach, we present results utilizing magnetic and gravity gradient data over part of the Gandarela Syncline iron formation in the Quadrilátero Ferrífero, Brazil.