Ocorrência de elementos terras raras nos rególitos do Batólito Pereiro e Faixa-Orós Jaguaribe

Abstract

This study aimed to investigate the potential occurrence of rare earth elements (REEs) in different geological units located in the southeastern portion of the state of Ceará and in the westernmost areas of the states of Rio Grande do Norte and Paraíba, Brazil. The research was based on prior planning involving cartographic analysis and interpretation of thorium (Th) geophysical anomalies, followed by fieldwork carried out in a single campaign with systematic sampling of rocks, altered rocks, and autochthonous soils. The samples were analyzed using Scanning Electron Microscopy coupled with Energy Dispersive Spectrometry (SEM–EDS), with emphasis on the granulometric fraction smaller than 0.125 mm. The results indicate that the augen gneisses of the Serra do Deserto Suite show the most significant REE enrichments, with the detection of yttrium (Y), lanthanum (La), neodymium (Nd), cerium (Ce), and hafnium (Hf), mainly associated with accessory minerals resistant to weathering. No significant REE anomalies were identified in the São Miguel Suite, Dr. Severiano Suite, or the Poço Dantas Pluton; however, localized enrichments of barium and tin were detected, the latter associated with hydrothermal environments. It is concluded that the integration of geophysical data, multiscale sampling, and SEM–EDS analyses proved effective in identifying areas favorable to REE concentration, highlighting the Serra do Deserto Suite as the unit with the greatest potential.