Feições morfológicas e biofácies como indicadores evolutivos da plataforma continental de Sergipe e sul de Alagoas

• Autor(a) principal: Santos, Jonas Ricardo dos
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: http://ri.ufs.br/jspui/handle/riufs/11309
• topic: Geomorfologia ambiental; Biofácies; Paleogeografia; Plataforma continental; Evolução paleogeográfica; Geomorfologia marinha; Indicadores evolutivos; Plataforma continental Sergipe-Alagoas; Biofacies; Continental shelf Sergipe-Alagoas; Marine geomorphology; Evolutionary indicators; Paleogeography evolution; OUTROS

The Sergipe-Alagoas continental shelf is characterized by being narrow and shallow. The aim of this thesis was to characterize the morphological and biophysical features of the continental shelf of Sergipe and south of Alagoas (SEAL), from the last glacial maximum and to infer a model of paleogeographic evolution. For the development of the work, the methodology was developed in a sequence of steps, where the data and analyzes of the available information were initially compiled. To identify and map the marine features on the continental shelf a bathymetric model was developed and the sediment samples collected in the oceanographic campaigns were analyzed and classified and distinguished the biofacies. For the elaboration of an evolutionary model of the platform will be correlated the morphological features and the occurrences of the different biofacies identified in the platform with the variations of sea level. The continental shelf SEAL presents a heterogeneity both in the geomorphological context and in relation to the bottom sediments of this region. The following features were identified on the SEAL platform: submerged and emerged reef alignments, high morphological submarines, bordered carbon banks, edge submarine terraces, underwater drainage, incised valleys and submarine canyons. The influence of the rivers in the continental shelf, the high submarine of Ponta dos Mangues and the canyons of São Francisco and Japaratuba stands out in this region. The bottom sediments analyzed allowed us to characterize the sedimentary distribution of the seabed and to identify the sedimentation of these sediments. This continental shelf is of the mixed siliciclastic-carbonate type and has a clear transition of the sedimentary composition with the increase of the depth, presenting the breaking of the platform to 45 m of depth. The biofacies are mainly composed of foraminifera, red algae and bryozoans. A wide morphological diversity was found in the continental shelf SEAL, both in the morphological features, sediments and biofacies that make up the bottom, being these correlates of previous events, evidencing the occurrence of environmental changes in the continental shelf due to the variations of the average level of the during transgressive and regressive periods.