Coastal Sedimentation in a Tropical Barrier-Island System During the Past Century in Sepetiba Bay, Brazil
The nature of sedimentation and sediment accumulation rates in Sepetiba Bay, Brazil were interpreted from grainsize patterns, natural radiochemical distributions and seismic stratigraphy. The grain-size analyses showed progressive upward fining of sediment in cores, and a higher percentage of clay...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Universidade Federal do Rio de Janeiro
2016-04-01
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| Series: | Anuário do Instituto de Geociências |
| Subjects: | |
| Online Access: | http://www.anuario.igeo.ufrj.br/2016_2/2016_2_05_14.pdf |
| _version_ | 1797966580194213888 |
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| author | Heloisa Vargas Borges Charles A. Nittrouer |
| author_facet | Heloisa Vargas Borges Charles A. Nittrouer |
| author_sort | Heloisa Vargas Borges |
| collection | DOAJ |
| description | The nature of sedimentation and sediment accumulation rates in Sepetiba Bay, Brazil were interpreted from grainsize
patterns, natural radiochemical distributions and seismic stratigraphy. The grain-size analyses showed progressive
upward fining of sediment in cores, and a higher percentage of clay in surficial deposits in 1996 than observed during a
previous spatial survey in the 1970s. Based on 210Pb geochronology, accumulation rates range from 0.37 cm yr-1 to 2.0 cm
yr-1 for the last hundred years. In contrast, seismic stratigraphy indicates a range from 0.01 to 0.17 cm yr-1 over the last
7000 years. Particularly high accumulation rates are found in the northeast part of the bay, and, as a consequence of these
high rates, the shoreline in the northern part of the bay prograded approximately 400 m in the last 100 years. An apparent
increase in accumulation rates and a tendency for deposits to fine upward over the last ~ 100 years are attributed to
human disturbance and soil erosion inland, which have been accelerated with economic development since the late 1970s. |
| first_indexed | 2024-04-11T02:17:38Z |
| format | Article |
| id | doaj.art-d16ae613fc0940868e4cf79cf681fa15 |
| institution | Directory Open Access Journal |
| issn | 0101-9759 1982-3908 |
| language | English |
| last_indexed | 2024-04-11T02:17:38Z |
| publishDate | 2016-04-01 |
| publisher | Universidade Federal do Rio de Janeiro |
| record_format | Article |
| series | Anuário do Instituto de Geociências |
| spelling | doaj.art-d16ae613fc0940868e4cf79cf681fa152023-01-03T00:51:28ZengUniversidade Federal do Rio de JaneiroAnuário do Instituto de Geociências0101-97591982-39082016-04-013920514http://dx.doi.org/10.11137/2016_2_05_14Coastal Sedimentation in a Tropical Barrier-Island System During the Past Century in Sepetiba Bay, BrazilHeloisa Vargas Borges0Charles A. Nittrouer1 Universidade Federal FluminenseUniversity of WashingtonThe nature of sedimentation and sediment accumulation rates in Sepetiba Bay, Brazil were interpreted from grainsize patterns, natural radiochemical distributions and seismic stratigraphy. The grain-size analyses showed progressive upward fining of sediment in cores, and a higher percentage of clay in surficial deposits in 1996 than observed during a previous spatial survey in the 1970s. Based on 210Pb geochronology, accumulation rates range from 0.37 cm yr-1 to 2.0 cm yr-1 for the last hundred years. In contrast, seismic stratigraphy indicates a range from 0.01 to 0.17 cm yr-1 over the last 7000 years. Particularly high accumulation rates are found in the northeast part of the bay, and, as a consequence of these high rates, the shoreline in the northern part of the bay prograded approximately 400 m in the last 100 years. An apparent increase in accumulation rates and a tendency for deposits to fine upward over the last ~ 100 years are attributed to human disturbance and soil erosion inland, which have been accelerated with economic development since the late 1970s.http://www.anuario.igeo.ufrj.br/2016_2/2016_2_05_14.pdf210Pb geochronologysedimentationSepetiba Bayseismic stratigraphy |
| spellingShingle | Heloisa Vargas Borges Charles A. Nittrouer Coastal Sedimentation in a Tropical Barrier-Island System During the Past Century in Sepetiba Bay, Brazil Anuário do Instituto de Geociências 210Pb geochronology sedimentation Sepetiba Bay seismic stratigraphy |
| title | Coastal Sedimentation in a Tropical Barrier-Island System During the Past Century in Sepetiba Bay, Brazil |
| title_full | Coastal Sedimentation in a Tropical Barrier-Island System During the Past Century in Sepetiba Bay, Brazil |
| title_fullStr | Coastal Sedimentation in a Tropical Barrier-Island System During the Past Century in Sepetiba Bay, Brazil |
| title_full_unstemmed | Coastal Sedimentation in a Tropical Barrier-Island System During the Past Century in Sepetiba Bay, Brazil |
| title_short | Coastal Sedimentation in a Tropical Barrier-Island System During the Past Century in Sepetiba Bay, Brazil |
| title_sort | coastal sedimentation in a tropical barrier island system during the past century in sepetiba bay brazil |
| topic | 210Pb geochronology sedimentation Sepetiba Bay seismic stratigraphy |
| url | http://www.anuario.igeo.ufrj.br/2016_2/2016_2_05_14.pdf |
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