Full text
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| Author(s): |
Luis Felipe Ferreira Batista
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2025-08-26 |
| Examining board members: |
Pablo Vidal Torrado;
Paulo Cesar Fonseca Giannini;
Fabiano do Nascimento Pupim
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| Advisor: | Pablo Vidal Torrado |
| Abstract | |
Meandering river floodplains exhibit landforms and environments that promote the accumulation of water and organic or inorganic sediments. Saturated and poorly drained settings favor the accumulation of organic matter, and when this process occurs intensely and persistently over time, it can give rise to peatlands. The soils of peatland ecosystems are Histosols, which are important carbon reservoirs and can be significant sources of methane emissions, storing about 30% of the worlds soil carbon. In Brazil, most studies on peatlands have focused on high-altitude environments. On the coastal plain in the southern part of São Paulo State, particularly along the Lower Ribeira de Iguape River (BRRI), approximately 70,000 hectares of Histosols have been mapped in reconnaissance-scale surveys, characterizing the region as one of the largest areas of occurrence of these soils in South America. This plain was affected by two marine transgressions (Late Pleistocene and Holocene), which altered the base level and strongly influenced the formation of sedimentary deposits and related landforms. This study discusses the relationships between landform evolution in the fluvial-estuarine plain of the BRRI and the genesis of coastal peatlands under palustrine forest in the subtropical region of Brazil, considering existing gaps regarding the origin and Late Quaternary evolution of these ecosystems. For this purpose, morphosedimentary units and their deposits were characterized and mapped; Opttically Stimulated Luminescence (OSL) and radiocarbon dating (14C) were carried out; and the soils were analyzed morphologically, chemically, and physically. The data obtained in the field and office work were integrated into the morphosedimentary mapping, which also used remote sensing tools and GIS software. The peatlands are associated with the formation of incised valleys that evolved into a ria-type estuarine system during the last (Holocene) marine transgression. During the closure of the plain by barrier islands, aquatic environments were colonized by aquatic plants through a process of terrestrialization followed by paludification, which led to the development of Histosols. Although the presence of peatlands is significant, the geomorphological evolution model associated with the morphosedimentary feature map suggests that the actual occurrence of Histosols in the BRRI is considerably lower than previously estimated by earlier reconnaissance-scale soil surveys for the Ribeira de Iguape Valley. (AU) | |
| FAPESP's process: | 24/03483-7 - Geomorphological evolution of the Lower Valley of Ribeira de Iguape River and implications for the Holocene peatlands genesis |
| Grantee: | Luis Felipe Ferreira Batista |
| Support Opportunities: | Scholarships in Brazil - Master |