Caracterização geomorfológica e análise da ocupação urbana da sub-bacia do Educandos, Manaus - Amazonas

Abstract

In the geomorphological context, analyzes of the drainage network, weathering profiles, morphodynamic processes, and interpretations on landscape evolution were integrated to determine the characteristics of the Educandos Sub-basin. Located in the urban area of the city of Manaus (AM), this sub-basin is an object of study aimed at explaining the behavior of some natural variables that governed its evolution. Geoforms with wavy relief, the development of chemical weathering profile derived from sediment change and sub-rectangular drainage network pattern, are diagnostic elements that support such interpretations. The weathering profile has a maximum depth of 8 meters, consisting of compact and erosion-resistant leaching horizons, covering a poorly evolved lateritic profile and to the transition profile base for non-consolidated siliciclastic (sandy) stratified sediments susceptible to concentrated erosion. Morphometric parameters of the basin show asymmetry, which would reflect the compartmentalization in two segments (high basin and low basin), defined from the lineage N60°W which section it. Morphological and drainage network alignments suggest that this segmentation is related to faulting and rotation of blocks, whose local effects controlled the evolution of the drainage network. Structures of a regional character and conjugate structures associated with a transcurrent shear system governed the layout of the main rivers of the region and the subordinate drainage network. The introduction of deeply modifying anthropogenic factors from natural morphodynamic processes resulted from changes in soil use. The urban mesh implantation involving the application of constructive systems that did not take into account the understanding of this natural dynamics, nor the intrinsic restrictions to it, are indicated as the main modifying causes of the natural landscape.