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| Author(s): |
Estéfano Seneme Gobbi
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Geociências |
| Defense date: | 2009-08-20 |
| Examining board members: |
Francisco Sérgio Bernardes Ladeira;
Regina Célia de Oliveira;
Cenira Maria Lupinacci da Cunha
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| Advisor: | Francisco Sérgio Bernardes Ladeira |
| Abstract | |
The Caraguatatuba's Sedimentary Plain can be considered as an exception in relation to other plains that surround it. Between the Canal de São Sebastião (SP) and Cabo Frio (RJ) predominate beaches discontinuous, segregated by indentations in the Planalto Atlântico, which sometimes suffer direct abrasion of the ocean. The beaches of the northern coast of São Paulo state and south of Rio de Janeiro state are known as "pocket beaches", presented by a plain sedimentation in small size in order to enter in some continent. However, in the Caraguatatuba's Plain, the scarped have a distance of 12 km to the current range of surf and the bay has an opening of about 10 km, unspoilt, so the other nearby plains. This fact is due to geological and structural factors, the Serra do Mar and the presence of alkaline intrusion of the São Sebastião, which allow the sedimentation in the area. This sedimentation occurs because sediment deposition by marine and / or river action. During the Quaternary period there were changes in relative sea level (glacio-eustatic variations), which showed advances and retreats of the coastline. Thus, to acquire higher levels, the marine abrasion reached certain thresholds altitude, eroding the scarped and depositing crystalline material in the current land area. Therefore, with changes in base level, the drainage network is undergoing a rearrangement, changing their statements, due to the variation of the energy transport. At the same time the marine deposits and fluvial deposits also occur through gravitational landslides of the scarped of the Serra do Mar. The genesis of this material is weathering the aggressive operating in Planalto Atlântico, making his cloak pedological. This fact, coupled with the proximity of the ocean and orographic barrier that is the Serra do Mar, causes intense rainfall, resulting in inherent in racing events and landslides, which is the deposition area of the Plain Sedimentary Caraguatatuba. The understandingans and spatialization of these events is the objective of this work that seeks to relate, in Caraguatatuba's Sedimentary Plain, marine, rivers and gravity sediments, for its genesis and evolution. The method of auger core and texture analysis, and laboratory analysis of samples collected in trenches are also checked. During the studies were verified instances of coarse material near the crystalline scarped, sometimes covered with clay-like material, which agrees with the hypotheses. (AU) | |