Gomes, Moab PraxedesSilva, Luzia Liniane do Nascimento2017-06-062017-06-062017-02-24SILVA, Luzia Liniane do Nascimento. Morfologia e sedimentologia dos recifes da plataforma continental externa norte do RN. 2017. 87f. Dissertação (Mestrado em Geodinâmica e Geofísica) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2017.https://repositorio.ufrn.br/jspui/handle/123456789/23405The outer continental shelf, northern Rio Grande do Norte is a zone of physiographic transition, sedimentological and oceanographic processes marked by eustatic variations of the Quaternary. In this study, we investigated the reef environments to understand the geodynamic evolution of the outer shelf. Therefore, the side scan sonar was used to map an area of 500 km², between the municipalities of Macau and São Bento do Norte, in parallel with the shelf break, in addition to 74 sedimentary samples and and the integration of the data with underwater photographs and bathymetry already existent to the area, in order to validate the sonographic interpretations.The main aims of this study are to understand how the antecedent geomorphology of the shelf can affect the development of the reefs, and how the reefs settled during the sea level Holocene variations. As a result, 7 backscatter patterns (P1 to P7) were associated with 11 sedimentary faceis (bioclastic and siliciclastic faceis), reefs distributed in mounds, sometimes oriented in the NW-SE direction, and the paleovalley of the Açu river. The bioclastic sand facies with granules is predominant, being related to the backscatter pattern P6. This sedimentary faceis is responsible for the high percentage of the organic matter and carbonate contents of the area. The reefs mapped are located in waters of 35 m depth, and themselves extend from tens to kilometers of meters. It is possible to see the alignment of these reefs, mainly in the western region, which may be indicative of antecedent substrates of old coastlines. In addition, the physiography of the shelf on steps and terraces, low sedimentation and rapid variations in sea level in the Holocene controlled the evolution of reefs.Acesso AbertoPlataforma externaRecifesSonografiaSedimentologiaMorfologiamasterThesisCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOFISICA