Pedogeochemistry of ultramafic soils from the Córrego dos Boiadeiros Body, Quadrilátero Ferrífero, Minas Gerais, Brazil

Abstract

The Córrego dos Boiadeiros Body (CBB) comprises a metaultramafic-metamafic sequence located in the vicinities of Nova Lima town, central area of the Quadrilátero Ferrífero province. The main rock type is a serpentinite that grades upwards to weathering mantles with well-preserved pedogenetic horizons composed, from bottom to top, of four facies: the R Horizon (Fresh rock facies), the C Horizon (Alterite facies), the B Horizon (Transition facies) and the A Horizon (Solum facies). This article presents the results of geochemical and mass balance studies along a representative pedogenetic profile in order to evaluate the chemical transformations concerning major, trace and Rare Earth Elements. From bottom to top of the selected profile, there is enrichment in Fe 2 O 3 , Al 2 O 3 and depletion in MgO and SiO 2. There are also relative gains of metallic elements as Ni, Co, V and loss of Au. Cr is enriched at the uppermost horizon. Pt is enriched at the basis of the profile, but decreases towards the upper layers. The weathering mantle is REE-enriched and shows major fractionating of LREE over HREE. In order to evaluate the economic potential of the lateritic deposits, especially concerning Cr content, additional chemical analyses should be distributed over the entire body and its surroundings.

APPLICATION OF pXRF (FIELD PORTABLE X-RAY FLUORESCENCE) TECHNIQUE IN FLUVIAL SEDIMENTS GEOCHEMICAL ANALYSIS – BULE STREAM, MINAS GERAIS STATE, BRAZIL

“…The good correlations of Cr with Zn and As represent an atypical case among the elements correlations. However, the relationship of Cr with chalcophile elements may reflect the influence of hydrothermal processes in shear zones between the units of the Rio das Velhas Supergroup, which have ultramafic rocks with significant Cr content (Nova Lima Group) (Fernandes et al, 2018), and units of the Minas Supergroup (supracrustal sequences).…”

Caracterização Tecnológica De Metapiroxenito Da Formação Córrego Dos Boiadeiros, Nova Lima (Mg), Brasil

“…In the Córrego dos Boiadeiros Formation, located in the central region of the Quadrilátero Ferrífero, near Nova Lima -MG, is the presence of meta-ultramafic rocks (serpentinite, steatite, chlorite tremolite shale and tremolite-serpentine granofels) and metamafics rocks (clinozoisiteactinolite granofels) (Fernandes et al, 2016(Fernandes et al, , 2018. In this region, the serpentinite is extracted for application as fundent in the steel industry.…”