Evidências de rearranjos fluviais no interflúvio Amazonas-Essequibo-Amazônia setentrional

• Autor(a) principal: Nascimento, Franzmiller Almeida
• Data de Publicação: 2019
• Outros Autores: Salgado, André Augusto Rodrigues, Gomes, António Alberto
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/10216/124787
• topic: Geografia; Geography

The Amazon region stands out, among several reasons, for presenting a mosaic of landscapes in the Amazon River'slarge fl uvial system. However, studies about the northern portion of this region still lack in depth, mainly in geologyand geomorphology. In this context, the Branco River basin - located in the State of Roraima, in Brazil, whichdrains towards the Amazon River but is located in the triple hydrographic divisor with those of the rivers Orinoco(Venezuela) and Essequibo (Guiana) - presents evidence of drainage rearrangement in several of its tributaries, asoccurs with the Maú River in the far northeast of the area, at the interfl ow between the Amazonas and Essequibobasins. Therefore, this study aims to interpret evidence of drainage rearrangement in Maú River's medium/lowcourse, such as river capture and alluvial deposits, by means of remote sensing images and morphometric dataobtained from DEM's. The analysis procedures were based on the interpretation of remote sensing images of thesatellite SENTINEL-2, 10x10 meters, MSI sensor, together with morphometric data obtained from the MDE'sALOS/PALSAR, 12.5x12.5 meters and SRTM/TOPODATA, 30x30 meters, in order to analyze the drainage network,morphological features and alluvial deposits. The interpreted data indicate that the fl uvial system of Maú River'smedium/low course suff ered little erosion because its regional base level had allowed lateral overfl ow and formationof a network of distributary paleochannels, constituting features of alluvial fans; the channels being tributariesof the Rupununi River (Essequibo Basin). Subsequently, a change in the regional base level of the Branco Riverapparently favored the capture of Maú River for the Amazon Hydrographic Basin, reorganizing the local drainagesystems and, consequently, promoting changes in the landscape. These conclusions clear the path for future studiesthat aim to assess the dates of the sedimentary deposits and thus track down the age of the fan systems and thecapture of the area drained by the Maú River into the Amazon basin.