Rare earth elements in gneiss regoliths in southern Minas Gerais, Brazil

Regolith characterization in its entirety is particularly difficult gneissic regoliths due to the heterogeneity of their rock structure. Rare earth elements (REE) are a useful tool helping understand evolution regoliths. This study relates mineralogy and weathering indexes three gneisses (P1-leucocratic, P2-mesocratic P3-melanocratic gneisses) distribution REE at depth. In soil, clay activity, iron manganese oxides, CaO, SiO2, P2O5, TiO2, Fe2O3, MgO showed high positive correlation with REE. The absolute content was enriched mafic minerals. At interface between soil saprolite, sum greater than saprolite P1, while opposite pattern found P2 P3. sums whole profiles did not overlap P3, concentration Gadolinium (Gd) differentiated all every horizon/layer without overlapping values. Normalized subsurface P1 Eu plagioclase, fractionation had less variation when estimated by Light / Heavy (LREE/HREE) La/Yb, since great (due segregation minerals into bands), low levels association Chemical Index Alteration (CIA) Weathering Parker (WIP).