Uso de dados aerogeofísicos de alta densidade para mapeamento geológico em terrenos altamente intemperizados: o estudo de caso da região de Cláudio, porção sul do Cráton São Francisco

Abstract

This paper presents an alternative way for mapping in highly weathered terrains using derivative products of high-density airborne geophysical data and their integration with geological data. The new products allowed a better definition of important geological features and supported the geological mapping in 1:100.000 scale. The region of Cla´udio, south part of Sa˜o Francisco Craton is comprised by Archean granite-gneissic terrains (TTG), an amphibolite unit and a supracrustal unit comprised by ultramafic rocks, amphibolites, schists, garnet-sillimanite quartzite and banded iron formation. The integrated approach incorporates the use of Ipatinga Sa˜o Joa˜o Del Rey airborne geophysical project and remote sensing data (Landsat-7/ Enhanced Thematic Mapper plus (ETM+)). The derivative products were groundedchecked to examine the efficiency of the magnetic and gamma-ray responses to delineate geological domains. The magnetometric maps provided information to the structural framework and about specific lithological units like mafic and ultramafic bodies, while the gamaespectrometric data brought strong insights about lithological units and boundaries. The data integration, which presents the geophysical and geomorphological characteristics of the lithological groups, shows high potential to better define geological contacts and tectonic structures in highly weathered Archean terrains.