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Seismic stratigraphy as indicator of late Pleistocene and Holocene sea level changes on the NE Brazilian continental shelf |
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| Institution: | 1. University of Bremen, MARUM – Center for Marine Environmental Sciences and Faculty of Geosciences, Klagenfurter Straße 4, D-28359 Bremen, Germany;2. División Geologia y Geofísica Marina, Departamento Oceanografía, Servicio de Hidrografía Naval, Montes de Oca 2124, C1270ABV Buenos Aires, Argentina;1. Univ. Bordeaux, CNRS, Bordeaux INP, EPOC, UMR 5805, F-33600 Pessac, France;2. Bureau de Recherche Géologique et Minière, Pessac, France;1. Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Am Alten Hafen 26, 27568 Bremerhaven, Germany;2. Deutsches Geoforschungszentrum Helmholtz-Zentrum Potsdam, Telegrafenberg, 14473 Potsdam, Germany;1. Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China;2. School of Earth and Environmental Sciences, The University of Queensland, QLD 4072, Australia;3. School of Geosciences, The University of Sydney, NSW 2006, Australia |
| Abstract: | The late Pleistocene Holocene stratigraphic architecture on the northeastern Brazilian continental shelf off the Parnaíba Delta has been explored by high-resolution seismic profiles. The seismic surveys reveal the widespread distribution of incised valleys of different size in offshore continuation of the present-day Parnaiba delta. According to morphology two channel types can be distinguished: U-shaped channels in the eastern part and V-shaped channels in the western part. The stratigraphic successions were grouped into four seismic units separated by different seismic boundaries. The characteristics of the seismic boundaries and internal reflectors of the seismic units were used to distinguish between marine and riverine deposits. The incised-valleys architectural elements were used to link sedimentation processes and variations in base level from late Pleistocene channel avulsion and channel infill in the lowermost course of the paleo-Parnaíba River to marine sediments of the present-day inner shelf. The change of the depositional environments in relation to deglacial sea-level rise is compared to incised valley infills of the Mekong River and Red River systems in Southeast Asia. |
| Keywords: | High resolution shallow-seismic Seismic-stratigraphy Incisedvalleys Sea-level change |
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