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| Author(s): |
Otávio Cardoso Cardona
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Filosofia, Letras e Ciências Humanas (FFLCH/SBD) |
| Defense date: | 2017-12-05 |
| Examining board members: |
Jose Pereira de Queiroz Neto;
Andreas Attila de Wolinsk Miklos;
Antonio Manoel dos Santos Oliveira;
Déborah de Oliveira;
Marcio Rossi
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| Advisor: | Jose Pereira de Queiroz Neto |
| Abstract | |
The Sorocá-Mirim River basin is located on the Ibiúna Plateau, wich is part of a set of failed blocks forming grabens and half grabens, which makes up a structural block system where water is trapped in sub-surface creating the ideal conditions for the formation of peatlands. Characteristics such as the geometry of interfluves, the asymmetry of slopes and flood plains and also the layout of the drainage network, denote the great influence of the geological structures in this basin. The areas of accumulation of organic matter found in the Sorocá-Mirim Basin are linked to particular fluvial environments, related to structural control, which is a characteristic feature of the area. The present study aimed to study peatlands in two different fluvial environments (terrace and amphitheater) in relation to their physical, chemical, and organic characteristics and their areolar distribution to understand how the formation of these peatlands was influenced by these environments. The topographic survey of the two areas, as well as a series of laboratory tests and analyzes showed that the peatlands of the two environments present different ages in approximately 1000 years (peatland of area 2 older than the peatland of area 1), same type of plants, accumulated along these years and differences mainly with respect to the preferential position to the accumulation of the organic matter and the variations, in the direction of the greater depths, of several observed parameters. It was verified that area 1 underwent major alterations in the landform, and consequently in its hydrological conditions over time, becoming a more drained, more oxygenated environment, with a peatland that presented more heterogenous laboratory results, with concentrations of organic matter and the elements attached to it, varying greatly throughout the feature. Area 2 did not undergo major alterations in the landform, remaining wetter over time which resulted in a more homogeneous peat with more constant values of organic matter and the elements bound to it, along the feature. These differences reflect the influence of landform on the processes of organic matter accumulation, where in each feature (terrace or amphitheater) the organic matter is accumulated in specific positions, suffering more or less interference of adjacent mineral materials; and mainly the landform controls the different hydrological conditions in each of the features, making the environment more or less moist and thus being the main element of control of the evolution processes of organic matter. The work showed that landform is the main conditioning element of the humidity of the environments and consequently of the processes of evolution and the characteristics of the peatlands. (AU) | |
| FAPESP's process: | 14/00011-5 - Peat bogs characterization in the Sorocá-Mirim River Basin, Ibiúna, SP |
| Grantee: | Otavio Cardoso Cardona |
| Support Opportunities: | Scholarships in Brazil - Doctorate |