Reconstrução ambiental e evolução sedimentar da região costeira de Icapuí/Ce por meio de processamento digital de imagens e análise de fácies

Abstract

This study was developed in the coastal plain of Icapuí, which is located in the eastern coast of the state of Ceará, located at brazilian northeast, and aimed to understand the sedimentary evolution related with the local coastal dynamics. The formation of continental beach ridges system seems to be influenced, in a regional perspective, by quaternary reactivations of a pair of conjugated faults composed by Carnaubais Fault (NE direction) and the Afonso Bezerra Fault (NW direction) and, in a local view, by Ponta Grossa – Fazenda Belém lineament (NNE-SSW), which appears to be one of the main mechanisms controlling deposition, suggesting a strong neotectonic influence on coastal morphology along the upper quaternary. Through the use of remote sensing images, sample collection and facies description in seven core samples, associated with granulometric and statistical analysis, was possible to describe 14 sandy facies dominated by fine-grained moderately-sorted with negative-asymmetric sediments. In some facies, was possible to see genetic relations using the analysis of three profiles in the study area, located in the eastern, central and western portions. Based on all the data obtained, it was possible to propose an evolution template that starts with the development of a spit in Tibau-RN, which developed pararell to the coastline to where the municipality of Icapuí is nowadays, promoting the backbarrier aggradation and the subsequent migration of the tidal channel from the SE-NW direction to S-N, a configuration compatible with the current coastline morphology.