This study defines some aspects of superficial alteration processes and their reflexes on the Quaternary pedogeomorphology in the sub-basin of the upper Maracujá River, in the Complexo Bação, ferriferous zone, State of Minas Gerais, Brazil. Characteristics related to the dynamic evolution of three gneiss-underlayered toposequences (1, 2, and 3) at different erosion stages were investigated. In the top slope segments of the toposequences 1 and 2 the soil profiles are little developed and present an in situ evolution. In toposequence 3, […]

The macro and micromorphological characteristics of the surface and subsurface diagnostic horizons of Oxisols and Quartzipsamments of the South American and Velhas geomorphic surfaces were analyzed in profiles under native vegetation cover, in order to establish a reference for future comparisons with similar areas under ongoing human intervention. The soils in their respective subregions and geomorphic surfaces were classified in three groups: Group 1: hypo to mesoferric, clayey to very clayey soils; Group 2: hypoferric; sandy to sandy loam soils, and Group 3: […]

A micropedological study was carried out in rehabilitated soils after bauxite mining, in sites dating from 1981 to 1987, compared with the Yellow Latosol, as reference, to subsidize soil indicators of rehabilitation. The study was located in Porto Trombetas, district of Oriximiná, northwestern Pará State. Micromorphological techniques, using EDS/SEM microprobe, optical and scanning electronic microscopy, were used in combination with chemical and physical analysis, at 0-10 and 40-50 cm depths. The Yellow Latosol showed a strong development of microgranular structure, […]

In the tropical humid environment, microbiotic crusts are widespread on exposed natural and antropic saprolites; yet, their biogeochemical and structural role is virtually ignored. In this work, the interactions involved in the biogeochemical weathering resultant of the action by microorganisms and inferior plants in gneiss saprolites of the Zona da Mata of Minas Gerais region were studied. The effects of organo-minerals associations on the formation and structural stabilization of the aggregates were investigated as well as the micropedological of features […]

The formation of soils with argillic horizons was investigated to identify the pedological processes involved in the formation of lamellae and the abrupt textural gradient as well as their implication on the soil physical, chemical and mineralogical attributes. This study was carried out on a sandstone-derived soil toposequence, with profile (P1) occupying the higher part of the landscape (summit), profile (P2) on the backslope, and profile (P3) on the footslope. Soil chemical, mineralogical, micromorphological and particle size distribution analyses were […]

On the landscape of the Eastern Plateau, north of the State of São Paulo, Brazil, there are ferricretes in different elevations. Although these features are relatively frequent over the cretaceous sandstone (Adamantina Formation, Bauru Group), little investigation has been carried out on their genesis. A morphological study at different levels of observation was conducted in order to elucidate the genesis of ferricretes (plinthite and petroplinthite), occurring at the toeslope of a landscape where soils with argillic horizon predominate, at the […]

In the region of Lavras, Minas Gerais, Brazil, soils profiles with argillic horizons were selected to evaluate the alterations which occurred during the process of soil formation and to investigate pedogenetic characteristics related to the parent material. Within this region, these soils occur on sloping and hilly landscapes. They were selected for this study because they preserve characteristics inherited from the original bedrocks. Three profiles formed from geologic material with different chemical composition were selected: Profile 1 – Red-Yellow Argisol […]

The town of Umuarama, Northwest of Paraná, presents sandy and medium-textured soil, derived from Cretaceous Caiuá Formation Sandstone. Besides the natural fragility of these soils, deforestation, use and generalized occupation have contributed to the identification of erosive processes. A slope next to the urban area was selected for a toposequence study aiming at a macro and micromorphological pedologic characterization followed by a physico-hydric characterization of the pedologic horizons. The data allowed to reach some important conclusions concerning material behavior, hydric […]