Petrografia e aerogamaespectrometria do granito tipo-A indiferenciado da região Uruará, SW do Pará

Abstract

The undifferentiated granitic stock A, is embedded in the Amazonian Classic, in the Iriri-Xingu, south of the Central Amazon Province, is located in the municipality of Uruará-PA, being basically composed of monzogranite and syenogranite with mafic content <6%. In general, these rocks are isotropic and have similar mineral content, being differentiated by the alkali feldspar content. The delimitation of the granitic body that finds these rocks was visually interpreted from the ternary map, with contributions from the K, Th and U single-channel maps, the Total Count map, maps of radiometric ratios U/K Th/K and U/Th. The ternary image together with the Shuttle Radar Topography Mission (SRTM) image and petrographic data. These studies show two distinct facies: porphyritic leukomonzogranite (LMGrP) that occupy most of the body and inequiganular leukosienogranite (LSGrI) that occur in smaller amounts. Furthermore, these data allow a better delimitation of this granite when compared to previous maps and a better individualization of the lithological facies. The spectropenetrant gamma proved to be a useful tool for many data integrated to the spectrometric gamma with geology, as the spectropenetrant gamma proved to be a useful tool for the characterization of granites, in addition to differences in their tools, delimiting this granitic stock with precision. Despite the already relevant contributions of this work, there is still a need to deepen knowledge, with more adequate mapping and studies that can determine the nature of chemical magic, with mineral and more accurate geochronological and isotopic data.