Métodos potenciais e espectrometria gama aplicados à exploração mineral de ferro e cobre no estado de Alagoas, Brasil.

Abstract

Geophysical interpretation has become increasingly important in identifying targets for mineral resource exploration in Brazil. The Transition Zone between the Pernambuco-Alagoas Domain and the Sergipano Belt, located in the Southern Borborema Province in Northeastern Brazil, is an example of a region that presents a vast potential for iron and copper exploration, disposing of an extensive collection of geophysical data and geological surveys. However, due to the lack of accessible geophysical investigations, the present research aimed to contribute to the region's gravity, magnetic, and radiometric investigations to identify other possible mineral regions for detailed examinations in addition to the known iron and copper exploration targets. Throughout the project, radiometric, gravimetric, and magnetic data were processed and used to characterize the study area and examine the potential mineral regions for copper and iron exploration in greater detail. To achieve the objective of this work, well-known methodologies were used to identify points of hydrothermal alteration, such as the F Factor and Anomalous Potassium, as well as methods for delineating contact zones and magnetic and gravimetric sources, such as the amplitude of the analytical signal and the total horizontal gradient. Taking advantage of quantitative and qualitative statistical data analysis, one of the outcomes of the work was the positive correlation between iron and copper occurrence points and regions with uranium and potassium enrichment, respectively. Three-dimensional density models were developed from the gravimetric data processed to understand better the substrate of the primary mineral sources identified in the region. From these results, information was extracted concerning the depth and volume of gravimetric sources, estimates of density contrasts between bodies and notions of the layout and structures in the subsoil. Given the conclusions presented, this study is further evidence of the range of possibilities geophysics can offer as a tool in mineral exploration.