Ortognaisses peraluminosos associados ao Grupo Araxá na região de Mairipotaba-Prof. Jamil Safady, Goiás

Abstract

Several gneissified granitic bodies occur in the southern region of Goiás State, Brazil, hosted in metassedimentary sequences from the Araxá Group. Two of these rock bodies are located in the outskirts of Mairipotaba and Cromínia, Professor Jamil Safady District, and display peraluminous, calc-alkaline compositions, been classified as S-type. These granitic bodies show low to medium content of alkali, large ion lithophile elements enrichment (Cs, Th, U, Ba, Rb, K) and light rare earth elements in relation to heavy rare earth elements and to high field strength elements (Zr, Y, Nb, Ta, Hf ). They also exhibit negative anomalies of Nb, Ta, P and Ti, similar to the chemical composition of magmas originated in magmatic arcs. Geochemical comparison between these rocks and the metasediments of the Araxá Group, in accordance to the geological context, indicates that the source of the magma that originated these granitic bodies is the metasediments from the Araxá Group.