Interpretation of aerogeophysycal and gravity data from Serra da Mesa region, Goiás and Tocantins

• Grant number: 11/19053-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2011
• End date: June 30, 2012
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geophysics
• Principal Investigator: Yára Regina Marangoni
• Grantee: Murilo Bellini Lacerda
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The Tocantins Province is located between the São Francisco craton to the east and the Amazon craton to the west. It is limited to the north and south by Parnaíba and Paraná sedimentary basins, respectively. The Research Company of Mineral Resources (CPRM) conducted an aerial survey in the area and provided magnetic and gamma spectrometry data, for the Serra da Mesa project. IAG has terrestrial gravity data in the study area. In the map of the total intensity of the magnetic field, two anomalies stand out at 48.8oW e 127oS. The shape of the anomalies, positive-negative-positive, almost aligned in the N-S direction indicates that the magnetization is almost exclusively induced, and near the magnetic equator (year of the survey: 1973). These magnetic anomalies have no gravity response, but the coverage area of gravity data is very poor, precluding correlation between data. In the geological map of the region, there are no mapped bodies in the coordinates of the anomalies, suggesting that these bodies do not outcrop. These anomalies appear to fit over linear magnetic structures, long and narrow in the NE-SW direction. It is intended to study and investigate these anomalies. For this, data will be analyzed using filters in the frequency domain, with the technique of FFT (Fast Fourier Transform), and techniques to emphasize the magnetic signal of the anomalies of interest and define the edges of the bodies. Other filters and processing can be implemented as needed. At the end, we will make an inversion of the body from the magnetic data.(AU)