Holocene climate pulses in southeast Brazil: geocronology of surficial cover in low fluvial, marine and fluvial-marine terraces in the Ribeira de Iguape (SP) and Paraíba do Sul (RJ) rivers

Author(s)

André de Oliveira Souza

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Geociências
• Defense date: 2019-09-09

Examining board members

Archimedes Perez Filho; Lúcio José Sobral da Cunha; José Cândido Stevaux; Emerson Martins Arruda; Regina Célia de Oliveira

• Advisor: Archimedes Perez Filho

Abstract

The importance of climate events, RSL oscillations and shoreline displacements for the geomorphological evolution of estuarine and delta systems in the southeastern Brazil, has been showed in several studies. Thus, many evidences of the mentioned processes can be found and studied through different proxies and in this research the different levels of low marine, fluviomarine and fluvial terraces are approached as geoindicators of marine transgressions and regressions triggered by Holocene climate pulses. Nevertheless, also is consider that these events may have been triggered by Holocene climate pulses worldwide recorded. In this sense, we seek to investigate the relationships between surficial cover on different levels of low terraces found in the Ribeira de Iguape (SP) estuary and Paraíba do Sul delta (RJ) with transgress-regress events and Holocene climate pulses. Therefore, the hypothesis this research is the spatializations of surficial cover on different terrace levels are geochronological related with Holocene coastal displacements triggered by climate anomalies. In this research, we performed grain-size, chemical, microscopy analysis and optically stimulated luminescence dating of surficial cover sampled in the different levels of low terraces. In addition, morphometric indexes were also used to identify structural controls on the deposit and drainage network spatializations. The results showed records of two marine transgression and regression events in the lower Ribeira de Iguape (SP). Meanwhile, in the Paraíba do Sul delta (RJ) a marine transgression event followed by two regressive pulses were identified. The ages of these events are geochronologically correlated with the Roman Warm Period, Dark Age Cold Period, Medieval Warm Period and Little Ice Age. Regarding the morphostructural analyzes, the results indicated that former structures acted conditioning the fluvial entrenchments during the regressions marine events (AU)

• FAPESP's process: 16/00382-9 - Geochronology of surface coverages in low fluvial terraces, Marine terraces and fluvial-Marine terraces at mouth of the Basins Ribeira de Iguape/SP and Paraíba South river: Holocene Climate fluctuation in the brazilian southeast
• Grantee: André de Oliveira Souza
• Support Opportunities: Scholarships in Brazil - Doctorate