Geomorphological description of the biome Pampa (Brazil) with support of digital elevation model and geographic information system

Abstract

In Brazil, the Pampa Biome is restricted to the far south in the state of Rio Grande do Sul, where it occupies an area of 176,496 km², which corresponds to 63% of the territory state and 2.07% of the Brazilian territory. The biome is characterized by the predominance of native fields with the presence of riparian forests, hillside forests, dwarf-palms fields, xerophyte bushes, wetlands, rocky outcrops, etc. Geomorphologically the landscape of the biome is very varied due to the lithological and structural conditions that interacted in the performance of surface processes. The landscapes consists of plains areas associated with Quaternary deposits; undulating reliefs associated with the sedimentary Basins, which consists of a volcano-sedimentary sequence by rocks formed in different depositional environments of the Paraná Basin and by rocks that represent a Plateau Volcanism and; a dissected plateau relief associated with the Precambrian crystalline basement. This paper describes quantitatively the relief through equations using Geographic Information Systems and the representation of the earth surface in the form of numerical digital models. Digital processing as well as the database were organized and managed by GIS, ArcGIS 10.3®, with spatial analysis and three-dimensional analysis tools. For each of the large geomorphological compartments that make up the Biome, a description of the landforms, and landforms elements were established and mapped. Relief shapes are described by the amplitude and slope of the terrain defined in flat areas, slightly undulations hills, undulating hills and large hills and buttes. For the determination of the relief elements the difference of topographic height, distance and the direction angle of the neighboring points in relation to the central cell (zenith and nadir angles) was used, through online application, available in the website << http://sil.uc.edu/geom/app >>. The relief elements determined are the flat, peak, ridge, shouder, spur, slope, hollow, footslope, valley, pit. The grouping of landforms and landform elements allowed the distinction of predominant morphological patterns for each geomorphological compartment in the Pampa Biome.