Análise da correlação e comportamento espacial dos elementos terras raras presentes em rochas e plantas na região do Complexo Intrusivo Lavras do Sul

Abstract

Rare earth elements are seventeen transition metals, with fifteen belonging to the lanthanide group and two to group three of the periodic table. Their utilization commenced in the 19th century, in gas lamps, and they are currently considered third-wave elements, due to their use in renewable energy, metallurgy, agriculture, and high-technology industry. Consequently, there has been an increase in demand and a growing wave of studies and research aimed at expanding the production of these elements. They are found in greater abundance in rocks associated with the Earth's crust, such as granites, alkaline rocks, carbonatites and placer-type deposits. Furthermore, rare earth elements can be found in plants, due to the adsorption of elements present in the substrate, by plant roots. In the present work, we intend to evaluate the existence of manifests and identify the spatial behavior of rare earth elements in rocks and plants of the Lavras do Sul Intrusive Complex. To do this, a database obtained from available bibliographies was used, consisting of chemical analyses of major, trace and rare earth elements. Uni and bivariate statistical analysis was applied to this database to identify trend measures. Geophysics was also used as a tool through the methods of gamma spectrometry and magnetometry, to identify anomalous points in the study area that may have links with ETRs. Based on the studies carried out, a positive correlation was found between the ETRs present in the rocks, with potassium oxide and thorium. The ETRs present in the plants had a positive correlation with the iron oxide present in the rocks. With regard to geophysics, it was possible to correlate the geophysical data of thorium and potassium with the concentrations of these elements in the rocks, making it possible to delimit the area of greatest occurrence of ETRs according to the lithology present in the area studied. Results similar to those in the literature were obtained in relation to the magnetometry geophysical method, as there was a higher concentration of ETRs at the edges of the intrusion. Therefore, the amount of ETRs present in the rocks has an indirect correlation with the concentration of these elements in plants, since pedogenetic processes and the types of minerals in the soil are the main agents of this concentration.