Gravity and magnetic integrated data interpretation of the corrégo dos bois complex, goiás alkaline province, central Brazil

Abstract

Previous studies carried out in some alkaline provinces around Paraná Basin, Brazil, show that most of the alkaline intrusions are related to high magnetic and gravity anomalies. In this study, both magnetic and gravity data are used to explore some of the alkaline intrusions of the Goiás Alkaline Province in Goiás state, near the northern Paraná Basin border. The total gradient and the normalized anisotropy variance methods were applied to detect the intrusions’ locations; they show a strong correlation between outcrops and sources for the main bodies. Then, by combining the 3-D inverted magnetization contrast from the magnetic data and the 2.5-D forward model from both the gravity and magnetic data, it was possible to set a mass distribution model for the intrusion of Córrego dos Bois. The results show that this intrusion extends from the surface to almost 10 km in depth, with a density contrast of 0.4 g/cm3 corresponding to a density value of 3.2 g/cm3, which is coherent with those shown in the literature for the rocks in the area. Magnetic inversion resulted in anomalies that are very similar but circa 200 nT lower that the observations at the positive lobe and no significant variation at the negative lobe.