Application Of Airborne Gamma-Ray Spectrometry In Granitic Intrusions Map-Ping: In The Western Of Sul-Riograndense Shield (Rs, Brasil)

Airborne gamma-ray spectrometry is a geophysical<br>method very important in the geological mapping,<br>because it is able to measure the chemical variation<br>of radioactive elements (K, Th and U). This<br>information can contribute significantly to an<br>analysis and to an individualization of granitics<br>intrusions. In this case, it was applied to granitic<br>intrusions in the western part of Sul-riograndense<br>Shield. The analysis of these geochemical<br>informations derived from the gamma-ray<br>spectrometry data permitted the discrimination of<br>eight granitic intrusions (CSGC, SSGC, LSIC and<br>Passo da Areia, Jaguari, Cerro das Marcas, Saibro<br>and Passo das Chácaras granites). Granitic intrusions<br>discriminated in airbone gamma-ray spectrometry<br>maps displayed a compositional variation (tonal<br>variation in K, U, Th and ternary maps). Tonal<br>variation enabled the characterization of granitics<br>bodies into calcium-alkaline, shoshonitic and alkaline granites.