Search

Pereira, S.D., Chaves, H.A.F., and Dos Santos, S.B., 2007. Evidence of sea level change at Guaratiba Mangrove, Sepetiba Bay, Brazil. (Proceedings of the 9th International Coastal Symposium), 1097 – 1100. Gold Coast, Australia, ISSN 0749.0208 Any change in sea level would lead to a migration from mangrove areas. In order to identify this migration, seven cores have been taken along a profile (SW-NE) in Guaratiba mangrove (Rio de Janeiro – Brazil) for sedimentological, biological and geochemical characterisation of the sedimentary sequence. Studies have shown the development of typical bottom bay sedimentation that corresponds to a transgressive event, consisting of muddy sediments and aged 6130 years B.P. at depth of 5.20 metres. According to bibliographical sources, this event reached its highest about 5100 years B.P., with the sea level reaching about 4.8 metres above present level. The area that corresponds to the regressive event is comprised predominantly of sand and silt. Bibliographical sources indicate this gradual rising of the sea level beginning about 4900 years B.P. When a new transgressive event begins, the layer of muddy sediment begins. Bibliographical sources indicate the occurrence of a transgressive event, over a shorter period (ca 3800 years B.P.) when the sea level rose about 3.0 metres. Since then, beginning a regressive event, characteristic sedimentation of lagunar and mangrove areas have been occurring. This last event might have occurred about 2400 years B.P. Considering transgressive and regressive periods, observed in the Guaratiba mangrove, in the Quaternary evolution of the Brazilian coast, it is possible to estimate that these periods are relayed to the last events of the Quaternary, corresponding to the Holocenic Highstand or Santos Transgression. [ABSTRACT FROM AUTHOR]