Quaternary evolution of rio itabapoana coastal plain and its relation with vulnerability

Quaternary evolution from Rio Itabapoana Coastal Plain is studied with the perspective of Geomorphology and field work. Seven stations were sampled, being one on the beach, where a profile was made comprising 3 ancient beach ridges. Sixteen samples were statistically analyzed, and morphoscopy and faciology were determined. As Holocenic beach-ridges are evident at the northern part of the river, it apparently stayed as a barrier-lagoon system for a long period before reaching the coast. When it happened, southward currents were more intense. The article finishes with a Quaternary evolution scheme regarding sea-level fluctuations. INTRODUCTION According to MARTIN et al. (1996), the state of Espírito Santo has two geomorphological units composing the landward boundaries separating the coastal plain from inland: a Tertiary plateau (Barreiras Formation) and another composed of crystalline rocks. Presidente Kennedy is located at the southern border of Espírito Santo, where this Plateau is in contact with the Quaternary deposits. The municipality is classified within the Sector 6, with a very important Quaternary deposit (MARTIN et al., 1996). The objective of the present work is to study the characteristics of Rio Itabapoana Coastal plain Quaternary evolution in comparison with other rivers in Brazil and correlate it with its vulnerability to inundation. MATERIAL AND METHODS Aerial photographs were first obtained from Instituto Estadual do Meio Ambiente (IEMA, 2008) and from RADAM survey (1970’s) in order to study the coastal plain evolution through Geomorphology and also to monitor morphological changes over time. After the definition of the coastal plain features a field survey was done, collecting subsuperficial samples for each geomorphological feature, in a total of five. One last station was surveyed with 3 samples (current riverbed). On the beach, a topographical profile was made, comprising 500 meters (3 ancient beach ridges), and one sample was collected, at the beach face. XIII Congresso da Associação Brasileira de Estudos do Quaternário ABEQUA III Encontro do Quaternário Sulamericano XIII ABEQUA Congress The South American Quaternary: Challenges and Perspectives