Magnetic and Gravity3D Modeling in the Basic Cenozoic Plug São João - Potiguar Basin.
Potential Methods, Geophysical modeling, magmatism Macau, Potiguar Basin.
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 hipoabissal plug known as São João, locatedin the southern border of the Potiguar Basin (NE Brazil). This plug has an area of approximately 0.5 km² and was formed by magmatism Macau, comprising a series of intrusive body in the northeastern portion of the Borborema Province along of the Macau-QueimadasAlignment. The 46 ± 4 Ma old São João plug is emplaced in the sedimentary sequences of the Açu and Jandaíra formations. Limestones and sandstones near 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 hipoabissal plug known as São João, locatedin the southern border of the Potiguar Basin (NE Brazil). This plug has an area of approximately 0.5 km² and was formed by magmatism Macau, comprising a series of intrusive body in the northeastern portion of the Borborema Province along of the Macau-QueimadasAlignment. The 46 ± 4 Ma old São João plug is emplaced in the sedimentary sequences of the Açu and Jandaíra formations. Limestones and sandstones near the hipoabissal body suffered metamorphization with significant thermal changes. We use airborne magneticdata 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 theairborne data contextualized regionally the geology and geophysics of the Potiguar Basin, while the terrestrial magnetic and gravimetric data detailed the plug São João and were used for the modeling. Magnetic susceptibility and density were measured in metamorphic(buchites) igneous (diabase, gabbro and microgabbro) and sedimentary (limestone and sandstone) rock samples. Such measures help to constrain the 2D and 3D modeling, which reveal the internal architecture of the São João plug, whose maximum depths reach 400m. The gravity model of the plug shows a geometry similar to a three-tips chandelier. The northeastern part of the magmatic body is characterized by higher density and magnetic susceptibility contrasts. Gravity highs closer to São João plug indicate threeregions with high density contrasts, which probably are igneous bodies with no surface expression. hipoabissal body suffered metamorphization with significant thermal changes. We use airborne magneticdata 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 theairborne data contextualized regionally the geology and geophysics of the Potiguar Basin, while the terrestrial magnetic and gravimetric data detailed the plug São João and were used for the modeling. Magnetic susceptibility and density were measured in metamorphic(buchites) igneous (diabase, gabbro and microgabbro) and sedimentary (limestone and sandstone) rock samples. Such measures help to constrain the 2D and 3D modeling, which reveal the internal architecture of the São João plug, whose maximum depths reach 400m. The gravity model of the plug shows a geometry similar to a three-tips chandelier. The northeastern part of the magmatic body is characterized by higher density and magnetic susceptibility contrasts. Gravity highs closer to São João plug indicate threeregions with high density contrasts, which probably are igneous bodies with no surface expression.