Sedimentação na bacia do Pantanal Mato-Grossense, Centro-Oeste do Brasil

The Pantanal is a Quaternary sedimentary basin located at the left margin of the Upper Paraguay River, west-central Brazil. Basin infilling was mainly by siliciclastic sediments and the stratigraphic succession exhibits an overall finingupward pattern. The depositional system tract is composed by a large meandering fluvial plain and several marginal alluvial fans, being the Taquari megafan the most striking feature. The present landscape is a complex tropical wetland, with geomorphic features derived from the present conditions and other inherited from successive Pleistocene and Holocene climates. During the Pleistocene, the sedimentary environment was dominated by braided alluvial fans, the original geometry of which is preserved as relict forms, permitting remarkable patterns of distributary paleochannels to be easily recognized in satellite images. Eolian processes were active in some abandoned lobes, contemporaneously with sedimentation in active fan lobes. Closed ponds bordered by lunette sand dunes, originally salt pans produced by eolian deflation, are relict eolian landforms in the Pantanal landscape. Eolian processes were probably more effective at the glacial maximum. Landscape has been changing in the Pantanal area since the end of the Pleistocene in adaptation to a more humid and warmer environment prevailing during Holocene. Initiation of the modern wetland has occurred during the Pleistocene / Holocene transition, with the change to a more humid climate and the individualization of lacustrine systems. The modern Pantanal wetland is a vast expanse of poorly drained lowlands that experiences annual flooding from summer to fall months. Although climatic fluctuations have occurred during all the Holocene, the alluvial fans have remained active depositional systems and lobes were formed by progradation and abandonment. Abandoned lobes were subjected... (Complete abstract click electronic address below)

Litofácies e relações estratigráficas da formação Aquidauana no nordeste da Bacia do Paraná - São Sebastião do Paraíso (MG)

The Aquidauana Formation is characterized by sandstones of variable granulation, mudstones and diamectites abundant in clay, typical colors like brick red (vermelho tijolo) of glacial, fluvial and lacustrine origin. It’s chronostratigraphic equivalent to the Itarará group from the Neo Carboniferous age, that under the exploratory view, such units represent important intervals in the basin, occurring together with them minerals as well as energy resources as petroleum, underground water and coal – what requires a great paleogeography and stratigraphy knowledge for its exploration. By gathering information from the columnar sections of the area, it was possible to characterize the sedimentary facies, the stacking pattern as well as the association. It was also made an attempt of stratigraphic correlation, which showed great difficulties since glacial environments present a great lateral discontinuity of the facies besides the complex relationship process of formation. As a result, it was obtained 8 sedimentary facies, the lateral and vertical relations and genesis process. It is proposed that the sedimentary environment in the study area is the fluvio glacial, characterized by alluvial systems formed by defrosted water which transport the sediments that are deposited in plains in front of the glacier (distal outwash). Petrographic thin section analysis showed that the transportation process was ineffective. The grains present punctual to lobular contacts, characterizing good porosity and permeability to the rock, varying these qualities according to more or less existence of matrix. The presence of Iron Oxide deposited between the recrystallization border and feldspathic mineral indicates that this rock has possibly presented a primary rubefaction, intensified by alkaline fluid percolation

A aplicação da abordagem do Tecnógeno na identificação e classificação dos terrenos e depósitos tecnogênicos no ambiente urbano de Guarapuava-PR

Pós-graduação em Geografia - FCT