Scanning Electron Microscopy (SEM) in the surficial cover analysis of the low fluvial-marine terraces in the southern coast of Sao Paulo state, Brazil

Author(s)

Souza, Andre de Oliveira ; Perez Filho, Archimedes

• Document type: Journal article
• Source: REVISTA BRASILEIRA DE GEOMORFOLOGIA; v. 23, n. 1, p. 17-pg., 2022-01-01.

Abstract

The Ribeira de Iguape estuarine system in Southeastern Brazil has resulted from the complex interactions between allogenic (climate, tectonics, and human interventions) and autogenic geomorphological processes. Early studies have shown that the relationship between sedimentary balances, fluvial discharge, and Holocene climate pulses resulted in the coastline displacement and low fluvial-marine terraces morphogenesis, which are composed of the marine and fluvial sedimentary units. In this perspective, this study aimed to investigate whether the microtextural and morphological records on the quartz grains associated with the different allostratigraphic units (marine and fluvial) correspond to the paleoenvironments identified in previous studies. In this study we have used a combination of analyses (grain-size, microtextural, and absolute dating) applied to the surficial cover sampled from two fluvial-marine terraces located on the right and left banks of the Iguape river channel. The results show correspondences between paleoenvironments and microtextures found on the quartz grains, confirming the statements addressed in previous studies that indicated the coastline was positioned about 9 km inland around 3.5-2.7 ka. (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
• FAPESP's process: 16/05327-6 - Spatial distribution and geochronology of surface coatings in marine, river- marine and river terraces in the context of climate fluctuations, associated to the Holocene's marine transgression and regression episodes in the Brazilian coast
• Grantee: Archimedes Perez Filho
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/07271-3 - Marine transgressions and regressions associated to Holocene climate pulsations: spacialization and geochronology of surface coverages in fluvial, fluvial-marine and marine terraces in the Brazilian coast
• Grantee: Archimedes Perez Filho
• Support Opportunities: Regular Research Grants