Resultados geofísicos integrados de um corpo com geometria 3D sem manifestação superficial

Abstract

Airborne geophysical data of the SP-RJ survey carried out by the Brazilian Geological Survey (CPRM) reveal a magnetic anomaly without geological expression at the surface. The anomalous features are similar to those associated with alkaline complexes that outcrop in the same region. The absence of surface elements motivated the use of different geophysical methods to characterize the magnetic anomaly source. Among these methods, satellite images for different spectral bands were used, seismic sounding, gravity and ground magnetic surveys along a profile crossing the anomaly were performed, and density and susceptibility measurements of different rock types in the area were made. The obtained results were used to constrain 2½D simultaneous gravity and magnetic modeling and 3D airborne magnetic modeling. Both results indicate the presence of a body of about 3.3 x 10(9) metric tons, having its top at 40 meters from the surface and extending to a maximum depth of 1 km.