This dissertation presents a geophysical study of a Cenozoic basic intrusion,involving steps of acquisition, processing, and 2D and 3D modeling of terrestrialmagnetic and gravity data. The target studied is a plug known as São João, located inthe southern border of the Potiguar Basin (NE Brazil). This plug has an area ofapproximately 0.5 km² and was formed by magmatism Macau. Sandstones andlimestones near the hipoabissal body suffered metamorphization with significantthermal changes. We use airborne magnetic data named Potiguar Basin Project andterrestrial acquisition, which resulted in 5698 readings with the total field magnetometerand 128 gravity stations with CG5 gravimeter. The map of vertical derivative of thetotal magnetic intensity anomalies from the airborne data contextualized regionally thegeology and geophysics of the Potiguar Basin, while the terrestrial magnetic andgravimetric data detailed the plug São João and were used for the modeling. Magneticsusceptibility and density were measured in metamorphic (buchites) igneous (diabase)and sedimentary (sandstone and limestone) rock samples. Such measures help toconstrain the 2D and 3D modeling, which reveal the internal architecture of the SãoJoão plug, whose maximum depths reach 400 m. The gravity model of the plug shows alopolith shape, with a region in the northeastern part of the body having higher densitycontrast. This region is also observed in the magnetic model with high contrast ofmagnetic susceptibility. Gravity highs closer to São João plug indicate three regionswith high density contrasts, which probably are igneous bodies with no surfaceexpression.
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