Geocronologia de formas deposicionais e evolução da planície interleques do Rio Negro, quartenário da Bacia do Pantanal

• Autor(a) principal: Mendes, Deborah [UNESP]
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/127654
• topic: Sedimentation and deposition; Sedimentação e depósitos; Tempo geológico; Bacias sedimentares; Pantanal Mato-grossense (MS e MT)

The southern portion of the Pantanal Wetlands is composed of the alluvial plains of the Taquari, Negro, Miranda, Taboco and Aquidauana rivers. The sedimentary dynamic of this region in driven by the interaction between these fluvial systems, in which the plain of Negro river is an important collector of the water that flows from the Taquari (Baixa Nhecolândia) and Aquidauana alluvial plains. The course of the Negro River is characterized by important changes in the fluvial style. The purpose of this research was the characterization of the compartments of the Negro River, with emphasis on their interfan stretch, in order to establish the relationship between the river and the megafans of Taquari and Aquidauana. Optically stimulated luminescence (OSL) was used as method to chronology of the sedimentary deposits. The geomorphological subdivision was based on remote sensing imagery, and the sediments were collected in accordance with the identified morphologies for later laboratorial analysis. Its springs are located in the Maracaju-Campo Grande plateau and after the course entering the Pantanal Wetlands, the river forms a plain implanted in sediments deposited by the Negro river ancient megafan. After an important deflection to the SW, the channel undergoes bifurcations, dividing it into anabranching channels in distributary plain. After new deflection to the W direction, it forms a plain located between megafans of Taquari and Aquidauana rivers, constituting its base level. The abrupt change in plain width promotes a significant change in fluvial style, because the channel begins to show multiple bifurcations, losing water to a wide and often flooded plain, whose waters are collected by Abobral and Miranda rivers. In the section studied in greater detail, the Negro river runs to W for about 50 km, forming interfan aggradational plain with low slope and built in a valley section. On this plain, the river is fed mainly by runoff coming from...