Avaliação da variabilidade geoquímica de elementos de terras raras, urânio e tório em perfis regolíticos/lateritizados em rochas do complexo jequié Bahia, Brasil
Resumo
The most common rare earth economic mineral deposits are associated with cacialcaline to
alkaline magmatic rocks and their products of the weathering. In this work, we present data
from drilling conducted in rare earth mineralized weathered rocks from Jequié Complex, in
Brazil. These rocks were subjected to intense weathering process, similar to what occurred in
the Ion Adsorption Clays deposits in southern China. The data analysis allowed the
classification of rare earth mineral resources with similar levels, sometimes higher than those
of the Chinese deposits, contained in the lateritic regolithic profile studied. The chemical index
of alteration (CIA) was adopted as a classification tool, horizontally separating the mineralized
weathering profile into six zones. The data indicated that there was a supergenic enrichment of
the REO in the lower portions of the profile and sometimes in the upper zones. The REO
average content ranged from 0.09% to 0.22% with maximum of 1.6%. The Th and U elements
tended to increase concentrations in the upper portions of the weathering profile, mainly
associated with laterization and high leaching zones. Based on the established lithochemical
classification, correlation matrices were designed to help define the possible phases of rare earth
occurrence in the weather profile. A model section representing the rare earth mineral deposit
of supergenic origin in rocks from Jequié / BA Complex was developed.