Exemplos de efeito tétrade nos lantanídeos em sistemas naturais

Abstract

The irregular patterns of rare earth elements, caused by the tetrad effect are revised and discussed in this work, covering its concept and subdivision into M and W types, quantification and the mechanisms that led to its occurrence in magmatic-hydrothermal and biological systems. M type patterns are more frequent in highly differentiated magmatic-hydrothermal systems, where volatile oversaturation and high activities of F are registered. M and W type patterns are registered in plants mostly as result of complexes absorption in the rhizosphere (W type), free-ions absorption by the plant (M type), or due to the pH variation and mineralogy of the soil. Examples of tetrad effects in plants, soils, minerals, and rocks are discussed in different geological contexts in the Pitinga Mine region, Amazonia, and in southernmost Brazil.