Mapeamento geomorfológico da folha Piumhi, Minas Gerais

Abstract

The Topographic Sheet of Piumhi (SF23VBII) in the Brazilian Systematic Mapping (scale 1:100.000), is located in the mid-west of Minas Gerais, in the Alto São Francisco area. This region attracts geographic interest both from an economic point of view and also from the academic community. This area corresponds to a diverse group of lithologies and morphologic types, due to its priviledged location in the São Francisco Craton. It is surrounded by a karstic landscape, with a great mineralogical potential, and also for geotourism, because of its amazing scenic beauty and relevance within the Brazilian karstic scenery, representing the carbonates of the Bambui group. The geological form of the area of study is a structuring element for the geomorphological variation found in the region, which, along with the climate and the structural controls, originated a geomorphological subdivision that varies from river plains, calcareous crusts, sierras, to various plateaus. The interest in creating the Geomorphologic Map of this area arises from the fact that it is an unpublished document, even considering that there is a great amount of existing works in other areas of study, such as geology. Furthermore, as already mentioned, it is notorious the physical diversity of the region and the mineralogical interest in it, which has put its environment in a very delicate situation because of the action of major mining companies in the area, that explore, mainly, carbonates. Having that in mind, the main object of this dissertation is to map the landforms and understand its geomorphological evolution and dynamics. The methodology is based in the approach of the concepts of morphostructure and morphosculpture, according to the hierarchization of landforms proposed by Ross (1992), and it also brings up the morphological, morphometric, morphogenetic and mophocronological characteristics of the area; with the use of geoprocessing tools (Geographic Information System). There were four Morphostructural Unities mapped as follows: Cenozoic Alluvial Deposits, Sedimentary Basin of São Francisco, Basement e System Jerks (Orogenetic Belt Brasilia). In relation to the Morphosculptural Unities, there are different types of genesis that classified the landforms in Aggradational, Dissectional, Karstic, Fluvio-Karstic and Structural. Moreover, the modeled or similar shape patterns were mapped, as well as the types of forms and also the structural lineaments running through the area. In short, the creation of the geomorphological map of the Piumhi Sheet offers the region a document filled with great geographic value, both in the geomorphology field and in any studies about the physical surroundings, integrated to the areas related to territorial planning and the environment.