A morfogênese e as transformações pedológicas, em parte dos córregos do Sepultura e do Contagem, região de Gouveia-MG como subsídio para o entendimento da evolução da paisagem

Abstract

This research aims to understand the evolution of the landscape and the possible causes of relief transformations, such as the formation of slopes due to the embedding of the watercourse, and the consequent transformation of the soils, resulting from the change in the local base level. The accumulation of organic material in places where there is no evidence of hydromorphism raised guiding questions to understand the evolutionary process of the landscape: is the loss of hydromorphism and the consequent transformation of organic soils into other classes of soils a result of the evolution of the local and regional landscape? Are the evolution of the landscape and the changes in relief resulting from the change in the local base level? The answers to the guiding questions were based on the following hypotheses: the area of hydromorphism is being altered by the opening of the valley caused by the embedding of the drainage and this is resulting in pedological changes; The loss of hydromorphism, the morphology of the slopes and the mechanisms of pedogenesis themselves may indicate that the hydromorphic cover is out of balance with the current pedobioclimatic conditions and that it once occupied a larger area; the loss of hydromorphism is causing many of the soils that present records of hydromorphic characteristics to transform into other classes of soils, without hydromorphic characteristics; the changes in the relief and landscape are the result of the change in the base level. To carry out the research, soil samples were collected and analyzed in the laboratory from some profiles of the study area, located in the region of the Camilinho Community, in the municipality of Gouveia-MG, along the Contagem and Sepultra streams. Chemical, granulometry, mineralogy and micromorphology analyses of the collected samples were carried out to investigate the evolution of these soils and their transformations, associating them with the landscape in which they are inserted. In addition, a database was collected from satellite images to create a digital elevation model, as well as from the creation of topographic profiles of the streams, with the aim of analyzing the altimetric drops along the streams and the possible knickpoints and knickzones resulting from the change in local base level. The soils near the top presented a certain homogeneity among their constituents, in addition to not presenting lithological discontinuities along the profiles, as confirmed by the absence of variation in the AF/AG ratio and by the more homogeneous mineralogical composition. The graphic material produced allowed the verification of variations in the altimetry, mainly altimetric drops along the course of the two streams, called knickpoints, which indicated changes in the local base level, which resulted in changes in the landscape, such as the formation of slopes from the fitting of the streams and the lowering of the relief to reach the base level, and in the soils present.