Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-12T15:09:55Z No. of bitstreams: 1 JulianaGarridoDamaceno_DISSERT.pdf: 4394873 bytes, checksum: f05a0b01011611585c6553b593f93fa0 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-19T16:25:56Z (GMT) No. of bitstreams: 1 JulianaGarridoDamaceno_DISSERT.pdf: 4394873 bytes, checksum: f05a0b01011611585c6553b593f93fa0 (MD5) / Made available in DSpace on 2017-01-19T16:25:56Z (GMT). No. of bitstreams: 1 JulianaGarridoDamaceno_DISSERT.pdf: 4394873 bytes, checksum: f05a0b01011611585c6553b593f93fa0 (MD5) Previous issue date: 2016-08-05 / Essa disserta??o apresenta um estudo geof?sico de uma intrus?o b?sica cenozoica, envolvendo etapas de aquisi??o, processamento e modelagens 2D e 3D de dados magn?ticos e gravim?tricos terrestres. O alvo estudado ? um plug conhecido como S?o Jo?o, intrusivo em rochas sedimentares da borda sul da Bacia Potiguar, regi?o setentrional do Rio Grande do Norte. Com uma ?rea aproximada de 0,5 km?, este plug ? um dos diversos corpos ?gneos constituintes do Magmatismo Macau (50-7 Ma). Os arenitos e calc?rios pr?ximos ao corpo subvulc?nico sofreram modifica??es mineral?gicas significativas por efeito termal. Utilizamos dados magn?ticos aerolevantados do Projeto Bacia Potiguar e aquisi??es terrestres, que resultaram em 5698 leituras com o magnet?metro de campo total e 128 esta??es gravim?tricas com o grav?metro CG5. O mapa das derivadas verticais do campo magn?tico an?malo dos dados a?reos contextualizou regionalmente a geologia e geof?sica da Bacia Potiguar, enquanto que os dados magn?ticos e gravim?tricos terrestres detalharam o plug S?o Jo?o e foram utilizados para as modelagens. Foram realizadas medidas de susceptibilidade magn?tica e densidade em amostras de rochas metam?rficas (buchitos), ?gneas (diab?sio) e sedimentares (arenito e calc?rio). Tais medidas auxiliaram na constru??o de modelos 2D e 3D, revelando a arquitetura interna do plug S?o Jo?o, cujas profundidades chegam a cerca de 400 m. O modelo gravim?trico apresenta uma geometria no formato de lop?lito, com uma regi?o na parte nordeste do corpo apresentando maiores contrastes de densidade. Tal regi?o ? tamb?m observada no modelo magn?tico, com altos contrastes de susceptibilidade magn?tica. M?ximos gravim?tricos pr?ximos ao plug indicam tr?s regi?es com contrastes de densidade positivos, que podem ser corpos ?gneos sem express?o em superf?cie. / This dissertation presents a geophysical study of a Cenozoic basic intrusion, involving steps of acquisition, processing, and 2D and 3D modeling of terrestrial magnetic and gravity data. The target studied is a plug known as S?o Jo?o, located in the southern border of the Potiguar Basin (NE Brazil). This plug has an area of approximately 0.5 km? and was formed by magmatism Macau. Sandstones and limestones near the hipoabissal body suffered metamorphization with significant thermal changes. We use airborne magnetic data named Potiguar Basin Project and terrestrial acquisition, which resulted in 5698 readings with the total field magnetometer and 128 gravity stations with CG5 gravimeter. The map of vertical derivative of the total magnetic intensity anomalies from the airborne data contextualized regionally the geology and geophysics of the Potiguar Basin, while the terrestrial magnetic and gravimetric data detailed the plug S?o Jo?o and were used for the modeling. Magnetic susceptibility and density were measured in metamorphic (buchites) igneous (diabase) and sedimentary (sandstone and limestone) rock samples. Such measures help to constrain the 2D and 3D modeling, which reveal the internal architecture of the S?o Jo?o plug, whose maximum depths reach 400 m. The gravity model of the plug shows a lopolith shape, with a region in the northeastern part of the body having higher density contrast. This region is also observed in the magnetic model with high contrast of magnetic susceptibility. Gravity highs closer to S?o Jo?o plug indicate three regions with high density contrasts, which probably are igneous bodies with no surface expression.