Physical and biological controis on lhe formalion of carbonate and siliciclaslic bedforms on lhe norlh-easl Brazilian shelf

Detalhes bibliográficos
Autor(a) principal: Testa, Viviane
Data de Publicação: 1999
Outros Autores: Bosence, Daniel W. J.
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional da UFBA
Texto Completo: http://www.repositorio.ufba.br/ri/handle/ri/5066
Resumo: p. 279—301
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spelling Testa, VivianeBosence, Daniel W. J.Testa, VivianeBosence, Daniel W. J.2012-01-09T12:44:32Z2012-01-09T12:44:32Z19991365-3091http://www.repositorio.ufba.br/ri/handle/ri/5066v.46p. 279—301The continental shelf of the State of Rio Grande do Norte, Brazil, is ani openi shelf area located 5°S and 35°W. It is influenced by strong oceanic and winddriven currents, fair weather, 15-m-high waves and a mesotidal regime. This work focuses on the character and the controls on the development of suites of carbonate and siliciclastic bedforms, based on Landsat TM image analysis and extensive ground-truth (diving) investigations. Large-scale bedforms consist of: (i) bioclastic (mainly coralline algae and Halimeda) sand ribbons (5—10 km long, 50—600 m wide) parallel to the shoreline; and (ii) very large transverse siliciclastic dunes (34 km long on average, 840 m spacing and 3—8 m high), with troughs that grade rapidly into carbonate sands and gravels. Wave ripples are superposed on ali large-scale bedforms, and indicate an onshore shelf sediment transport normal to the main sediment transport direction. The occurrence of these large-scale bedforms is primarily determined by the northwesterly flowing residual oceanic and tidal currents, resulting mainly in coastparallel transport. Models of shelf bedform formation predict sand ribbons to occur in higher energy settings rather than in large dunes. However, in the study area, sand ribbons occur in an area of coarse, low-density and easily transportable bioclastic sands and gravels compared with the very large transverse dunes in an offshore area that is composed of denser mediumgrained siliciclastic sands. It suggests that the availability of different sediment types is likely to exert an influence on the nature of the bedforms generated. The offshore sand supply is time limited and originates from sea floor erosion of sandstones of former sea-level lowstands. The trough areas of both sand ribbons and very large transverse dunes comprise coarse calcareous algal gravels that support benthic communities of variable maturity. Diverse mature communities result in sediment stabilization through branching algal growth and binding that is thought to modify the morphology of dunes and sand ribbons. The occurrence and the nature of the bedforms is controlled by their hydrodynamic setting, by grain composition that reflects the geological history of the area and by the carbonate-producing benthic marine communities that inhabit the trough areas.Submitted by Ana Valéria de Jesus Moura (anavaleria_131@hotmail.com) on 2012-01-09T12:44:32Z No. of bitstreams: 1 Physical_biological_controls_on_carbonate_sandbars_NE_Brazil_shelf.pdf: 2000111 bytes, checksum: b795e4ba78c2a842cf3780a38687d905 (MD5)Made available in DSpace on 2012-01-09T12:44:32Z (GMT). No. of bitstreams: 1 Physical_biological_controls_on_carbonate_sandbars_NE_Brazil_shelf.pdf: 2000111 bytes, checksum: b795e4ba78c2a842cf3780a38687d905 (MD5) Previous issue date: 1999Bedformscarbonate shelfcurrent-dominatednorth-east Brazilsand ribbonsPhysical and biological controis on lhe formalion of carbonate and siliciclaslic bedforms on lhe norlh-easl Brazilian shelfSedimentologyinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleengreponame:Repositório Institucional da UFBAinstname:Universidade Federal da Bahia (UFBA)instacron:UFBAinfo:eu-repo/semantics/openAccessORIGINALPhysical_biological_controls_on_carbonate_sandbars_NE_Brazil_shelf.pdfPhysical_biological_controls_on_carbonate_sandbars_NE_Brazil_shelf.pdfapplication/pdf2000111https://repositorio.ufba.br/bitstream/ri/5066/1/Physical_biological_controls_on_carbonate_sandbars_NE_Brazil_shelf.pdfb795e4ba78c2a842cf3780a38687d905MD51LICENSElicense.txtlicense.txttext/plain1762https://repositorio.ufba.br/bitstream/ri/5066/2/license.txt1b89a9a0548218172d7c829f87a0eab9MD52TEXTPhysical_biological_controls_on_carbonate_sandbars_NE_Brazil_shelf.pdf.txtPhysical_biological_controls_on_carbonate_sandbars_NE_Brazil_shelf.pdf.txtExtracted texttext/plain80599https://repositorio.ufba.br/bitstream/ri/5066/3/Physical_biological_controls_on_carbonate_sandbars_NE_Brazil_shelf.pdf.txtd90af4ad54007ac05fbe0bfad9182628MD53ri/50662022-07-05 14:03:17.278oai:repositorio.ufba.br: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Repositório InstitucionalPUBhttp://192.188.11.11:8080/oai/requestopendoar:19322022-07-05T17:03:17Repositório Institucional da UFBA - Universidade Federal da Bahia (UFBA)false
dc.title.pt_BR.fl_str_mv Physical and biological controis on lhe formalion of carbonate and siliciclaslic bedforms on lhe norlh-easl Brazilian shelf
dc.title.alternative.pt_BR.fl_str_mv Sedimentology
title Physical and biological controis on lhe formalion of carbonate and siliciclaslic bedforms on lhe norlh-easl Brazilian shelf
spellingShingle Physical and biological controis on lhe formalion of carbonate and siliciclaslic bedforms on lhe norlh-easl Brazilian shelf
Testa, Viviane
Bedforms
carbonate shelf
current-dominated
north-east Brazil
sand ribbons
title_short Physical and biological controis on lhe formalion of carbonate and siliciclaslic bedforms on lhe norlh-easl Brazilian shelf
title_full Physical and biological controis on lhe formalion of carbonate and siliciclaslic bedforms on lhe norlh-easl Brazilian shelf
title_fullStr Physical and biological controis on lhe formalion of carbonate and siliciclaslic bedforms on lhe norlh-easl Brazilian shelf
title_full_unstemmed Physical and biological controis on lhe formalion of carbonate and siliciclaslic bedforms on lhe norlh-easl Brazilian shelf
title_sort Physical and biological controis on lhe formalion of carbonate and siliciclaslic bedforms on lhe norlh-easl Brazilian shelf
author Testa, Viviane
author_facet Testa, Viviane
Bosence, Daniel W. J.
author_role author
author2 Bosence, Daniel W. J.
author2_role author
dc.contributor.author.fl_str_mv Testa, Viviane
Bosence, Daniel W. J.
Testa, Viviane
Bosence, Daniel W. J.
dc.subject.por.fl_str_mv Bedforms
carbonate shelf
current-dominated
north-east Brazil
sand ribbons
topic Bedforms
carbonate shelf
current-dominated
north-east Brazil
sand ribbons
description p. 279—301
publishDate 1999
dc.date.issued.fl_str_mv 1999
dc.date.accessioned.fl_str_mv 2012-01-09T12:44:32Z
dc.date.available.fl_str_mv 2012-01-09T12:44:32Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://www.repositorio.ufba.br/ri/handle/ri/5066
dc.identifier.issn.none.fl_str_mv 1365-3091
dc.identifier.number.pt_BR.fl_str_mv v.46
identifier_str_mv 1365-3091
v.46
url http://www.repositorio.ufba.br/ri/handle/ri/5066
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
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dc.source.none.fl_str_mv reponame:Repositório Institucional da UFBA
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instname_str Universidade Federal da Bahia (UFBA)
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reponame_str Repositório Institucional da UFBA
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