Heat Flow of Basement Adjacent to the Sergipe-Alagoas Sedimentary Basin (Northeast Brazil) from the Aeromagnetic Data and Curie Depth
Alanna Costa Dutra *
Department of Earth Physics and Environment, Physics Institute, Federal University of Bahia, Brazil
Roberto Max de Argollo
Department of Earth Physics and Environment, Physics Institute, Federal University of Bahia, Brazil
Alexandre Barreto Costa
Department of Earth Physics and Environment, Physics Institute, Federal University of Bahia, Brazil
*Author to whom correspondence should be addressed.
Abstract
- The present project aims at the processing and interpretation of magnetic data along the basement adjacent to the Sergipe-Alagoas Sedimentary, Southern Borborema Province, and northeast Brazil. The magnetic and geological studies were developed simultaneously to make a magnetic modeling of the crustal domains and their tectonic relationships to construct a model of the geothermal structure of the crust for the region. The first part of the study consisted in to delineate contacts and border of the geologic formation. These magnetic sources have signals with various amplitudes that originate from different geometric sources, situated at different depths and with different magnetic properties. The second part consisted in to estimate of the depth of the main domains and Curie point in the study region and the knowledge of the Curie depth allows the subsequent estimation of the geothermal gradient and thermal flow in the region. The results obtained from the analysis of the magnetic anomalies shows the Curie point depth of from the 13 up to 33 km. The Curie point depth indicates the bottom depth of magnetic sources and reflects the thermal gradient and the observed heat flow data. The thermal gradient varies from the 15°C/km up to 35°C/k and the heat flow varies from the 38 mW/m² up to 90 mW/m² heat flow. We compared results to the available the layers carry a magnetic signature and plunge at a significant angle, a detailed magnetic investigation was used to map the very precise surface geology. The present result was compared with the tectonic and heat flow data.
Keywords: Sedimentary basin, curie depth, heat flow, thermal gradient, aeromagnetic data