Large barchanoid dunes in the Amazon River and the rock record : implications for interpreting large river systems.
Autor(a) principal: | |
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Data de Publicação: | 2016 |
Outros Autores: | , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFOP |
Texto Completo: | http://www.repositorio.ufop.br/handle/123456789/8831 https://doi.org/10.1016/j.epsl.2016.08.029 |
Resumo: | The interpretation of large river deposits from the rock record is hampered by the scarcity of direct observations of active large river systems. That is particularly true for deep-channel environments, where tens of meters deep flows dominate. These conditions are extremely different from what is found in smaller systems, from which current facies models were derived. MBES and shallow seismic surveys in a selected area of the Upper Amazonas River in Northern Brazil revealed the presence of large compound barchanoid dunes along the channel thalweg. The dunes are characterized by V-shaped, concave-downstream crest lines and convex-up longitudinal profiles, hundreds of meters wide, up to 300 m in wavelength and several meters high. Based on the morphology of compound dunes, expected preserved sedimentary structures are broad, large-scale, low-angle, concave up and downstream cross-strata, passing laterally and downstream to inclined cosets. Examples of such structures from large river deposits in the rock record are described in the Silurian Serra Grande Group and the Cretaceous São Sebastião and Marizal formations in Northeastern Brazil, as well as in Triassic Hawkesburry Sandstone in Southeastern Australia and the Plio–Pleistocene Içá Formation in the western Amazon. All these sedimentary structures are found near channel base surfaces and are somewhat coarser than the overlying fluvial deposits, favoring the interpretation of thalweg depositional settings. The recognition of large barchanoid dunes as bedforms restricted to river thalwegs and probably to large river systems brings the possibility of establishing new criteria for the interpretation of fluvial system scale in the rock record. Sedimentary structures compatible with the morphological characteristics of these bedforms seem to be relatively common in large river deposits, given their initial recognition in five different fluvial successions in Brazil and Australia, potentially enabling substantial improvements in facies models for large rivers. |
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Almeida, Renato Paes deGaleazzi, Cristiano PadalinoFreitas, Bernardo TavaresJanikian, LilianeIanniruberto, MarcoMarconato, André2017-10-02T13:53:30Z2017-10-02T13:53:30Z2016ALMEIDA, R. P. de et al. Large barchanoid dunes in the Amazon River and the rock record: implications for interpreting large river systems. Earth and Planetary Science Letters, v. 454, p. 92-102, 2016. Disponível em: <http://www.sciencedirect.com/science/article/pii/S0012821X16304587>. Acesso em: 25 ago. 2017.0012-821Xhttp://www.repositorio.ufop.br/handle/123456789/8831https://doi.org/10.1016/j.epsl.2016.08.029The interpretation of large river deposits from the rock record is hampered by the scarcity of direct observations of active large river systems. That is particularly true for deep-channel environments, where tens of meters deep flows dominate. These conditions are extremely different from what is found in smaller systems, from which current facies models were derived. MBES and shallow seismic surveys in a selected area of the Upper Amazonas River in Northern Brazil revealed the presence of large compound barchanoid dunes along the channel thalweg. The dunes are characterized by V-shaped, concave-downstream crest lines and convex-up longitudinal profiles, hundreds of meters wide, up to 300 m in wavelength and several meters high. Based on the morphology of compound dunes, expected preserved sedimentary structures are broad, large-scale, low-angle, concave up and downstream cross-strata, passing laterally and downstream to inclined cosets. Examples of such structures from large river deposits in the rock record are described in the Silurian Serra Grande Group and the Cretaceous São Sebastião and Marizal formations in Northeastern Brazil, as well as in Triassic Hawkesburry Sandstone in Southeastern Australia and the Plio–Pleistocene Içá Formation in the western Amazon. All these sedimentary structures are found near channel base surfaces and are somewhat coarser than the overlying fluvial deposits, favoring the interpretation of thalweg depositional settings. The recognition of large barchanoid dunes as bedforms restricted to river thalwegs and probably to large river systems brings the possibility of establishing new criteria for the interpretation of fluvial system scale in the rock record. Sedimentary structures compatible with the morphological characteristics of these bedforms seem to be relatively common in large river deposits, given their initial recognition in five different fluvial successions in Brazil and Australia, potentially enabling substantial improvements in facies models for large rivers.O periódico Earth and Planetary Science Letters concede permissão para depósito deste artigo no Repositório Institucional da UFOP. Número da licença: 4193050613957.info:eu-repo/semantics/openAccessLarge rivers sedimentaryThalweg bedformsMultibeam echosounderStructuresLarge barchanoid dunes in the Amazon River and the rock record : implications for interpreting large river systems.info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleengreponame:Repositório Institucional da UFOPinstname:Universidade Federal de Ouro Preto (UFOP)instacron:UFOPLICENSElicense.txtlicense.txttext/plain; charset=utf-8924http://www.repositorio.ufop.br/bitstream/123456789/8831/2/license.txt62604f8d955274beb56c80ce1ee5dcaeMD52ORIGINALARTIGO_LargeBarchanoidDunes.pdfARTIGO_LargeBarchanoidDunes.pdfapplication/pdf4570553http://www.repositorio.ufop.br/bitstream/123456789/8831/1/ARTIGO_LargeBarchanoidDunes.pdf62d913d1ea0bea0c64b2df58173f4058MD51123456789/88312020-02-03 09:40:06.782oai:localhost: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ório InstitucionalPUBhttp://www.repositorio.ufop.br/oai/requestrepositorio@ufop.edu.bropendoar:32332020-02-03T14:40:06Repositório Institucional da UFOP - Universidade Federal de Ouro Preto (UFOP)false |
dc.title.pt_BR.fl_str_mv |
Large barchanoid dunes in the Amazon River and the rock record : implications for interpreting large river systems. |
title |
Large barchanoid dunes in the Amazon River and the rock record : implications for interpreting large river systems. |
spellingShingle |
Large barchanoid dunes in the Amazon River and the rock record : implications for interpreting large river systems. Almeida, Renato Paes de Large rivers sedimentary Thalweg bedforms Multibeam echosounder Structures |
title_short |
Large barchanoid dunes in the Amazon River and the rock record : implications for interpreting large river systems. |
title_full |
Large barchanoid dunes in the Amazon River and the rock record : implications for interpreting large river systems. |
title_fullStr |
Large barchanoid dunes in the Amazon River and the rock record : implications for interpreting large river systems. |
title_full_unstemmed |
Large barchanoid dunes in the Amazon River and the rock record : implications for interpreting large river systems. |
title_sort |
Large barchanoid dunes in the Amazon River and the rock record : implications for interpreting large river systems. |
author |
Almeida, Renato Paes de |
author_facet |
Almeida, Renato Paes de Galeazzi, Cristiano Padalino Freitas, Bernardo Tavares Janikian, Liliane Ianniruberto, Marco Marconato, André |
author_role |
author |
author2 |
Galeazzi, Cristiano Padalino Freitas, Bernardo Tavares Janikian, Liliane Ianniruberto, Marco Marconato, André |
author2_role |
author author author author author |
dc.contributor.author.fl_str_mv |
Almeida, Renato Paes de Galeazzi, Cristiano Padalino Freitas, Bernardo Tavares Janikian, Liliane Ianniruberto, Marco Marconato, André |
dc.subject.por.fl_str_mv |
Large rivers sedimentary Thalweg bedforms Multibeam echosounder Structures |
topic |
Large rivers sedimentary Thalweg bedforms Multibeam echosounder Structures |
description |
The interpretation of large river deposits from the rock record is hampered by the scarcity of direct observations of active large river systems. That is particularly true for deep-channel environments, where tens of meters deep flows dominate. These conditions are extremely different from what is found in smaller systems, from which current facies models were derived. MBES and shallow seismic surveys in a selected area of the Upper Amazonas River in Northern Brazil revealed the presence of large compound barchanoid dunes along the channel thalweg. The dunes are characterized by V-shaped, concave-downstream crest lines and convex-up longitudinal profiles, hundreds of meters wide, up to 300 m in wavelength and several meters high. Based on the morphology of compound dunes, expected preserved sedimentary structures are broad, large-scale, low-angle, concave up and downstream cross-strata, passing laterally and downstream to inclined cosets. Examples of such structures from large river deposits in the rock record are described in the Silurian Serra Grande Group and the Cretaceous São Sebastião and Marizal formations in Northeastern Brazil, as well as in Triassic Hawkesburry Sandstone in Southeastern Australia and the Plio–Pleistocene Içá Formation in the western Amazon. All these sedimentary structures are found near channel base surfaces and are somewhat coarser than the overlying fluvial deposits, favoring the interpretation of thalweg depositional settings. The recognition of large barchanoid dunes as bedforms restricted to river thalwegs and probably to large river systems brings the possibility of establishing new criteria for the interpretation of fluvial system scale in the rock record. Sedimentary structures compatible with the morphological characteristics of these bedforms seem to be relatively common in large river deposits, given their initial recognition in five different fluvial successions in Brazil and Australia, potentially enabling substantial improvements in facies models for large rivers. |
publishDate |
2016 |
dc.date.issued.fl_str_mv |
2016 |
dc.date.accessioned.fl_str_mv |
2017-10-02T13:53:30Z |
dc.date.available.fl_str_mv |
2017-10-02T13:53:30Z |
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.citation.fl_str_mv |
ALMEIDA, R. P. de et al. Large barchanoid dunes in the Amazon River and the rock record: implications for interpreting large river systems. Earth and Planetary Science Letters, v. 454, p. 92-102, 2016. Disponível em: <http://www.sciencedirect.com/science/article/pii/S0012821X16304587>. Acesso em: 25 ago. 2017. |
dc.identifier.uri.fl_str_mv |
http://www.repositorio.ufop.br/handle/123456789/8831 |
dc.identifier.issn.none.fl_str_mv |
0012-821X |
dc.identifier.doi.none.fl_str_mv |
https://doi.org/10.1016/j.epsl.2016.08.029 |
identifier_str_mv |
ALMEIDA, R. P. de et al. Large barchanoid dunes in the Amazon River and the rock record: implications for interpreting large river systems. Earth and Planetary Science Letters, v. 454, p. 92-102, 2016. Disponível em: <http://www.sciencedirect.com/science/article/pii/S0012821X16304587>. Acesso em: 25 ago. 2017. 0012-821X |
url |
http://www.repositorio.ufop.br/handle/123456789/8831 https://doi.org/10.1016/j.epsl.2016.08.029 |
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eng |
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