The insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution
Autor(a) principal: | |
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Data de Publicação: | 2015 |
Outros Autores: | , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.21/6109 |
Resumo: | Shelves surrounding reefless volcanic ocean islands are formed by surf erosion of their slopes during changing sea levels. Posterosional lava flows, if abundant, can cross the coastal cliffs and fill partially or completely the accommodation space left by erosion. In this study, multibeam bathymetry, high-resolution seismic reflection profiles, and sediment samples are used to characterize the morphology of the insular shelves adjacent to Pico Island. The data show offshore fresh lava flow morphologies, as well as an irregular basement beneath shelf sedimentary bodies and reduced shelf width adjacent to older volcanic edifices in Pico. These observations suggest that these shelves have been significantly filled by volcanic progradation and can thus be classified as rejuvenated. Despite the general volcanic infilling of the shelves around Pico, most of their edges are below the depth of the Last Glacial Maximum, revealing that at least parts of the island have subsided after the shelves formed by surf erosion. Prograding lava deltas reached the shelf edge in some areas triggering small slope failures, locally decreasing the shelf width and depth of their edges. These areas can represent a significant risk for the local population; hence, their identification can be useful for hazard assessment and contribute to wiser land use planning. Shelf and subaerial geomorphology, magnetic anomalies and crustal structure data of the two islands were also interpreted to reconstruct the long-term combined onshore and offshore evolution of the Faial-Pico ridge. The subaerial emergence of this ridge is apparently older than previously thought, i.e., before approximate to 850 ka. |
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The insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolutionVolcanic ocean islandShelf developmentCoastal erosionLava progradationMass wastingGeological evolutionShelves surrounding reefless volcanic ocean islands are formed by surf erosion of their slopes during changing sea levels. Posterosional lava flows, if abundant, can cross the coastal cliffs and fill partially or completely the accommodation space left by erosion. In this study, multibeam bathymetry, high-resolution seismic reflection profiles, and sediment samples are used to characterize the morphology of the insular shelves adjacent to Pico Island. The data show offshore fresh lava flow morphologies, as well as an irregular basement beneath shelf sedimentary bodies and reduced shelf width adjacent to older volcanic edifices in Pico. These observations suggest that these shelves have been significantly filled by volcanic progradation and can thus be classified as rejuvenated. Despite the general volcanic infilling of the shelves around Pico, most of their edges are below the depth of the Last Glacial Maximum, revealing that at least parts of the island have subsided after the shelves formed by surf erosion. Prograding lava deltas reached the shelf edge in some areas triggering small slope failures, locally decreasing the shelf width and depth of their edges. These areas can represent a significant risk for the local population; hence, their identification can be useful for hazard assessment and contribute to wiser land use planning. Shelf and subaerial geomorphology, magnetic anomalies and crustal structure data of the two islands were also interpreted to reconstruct the long-term combined onshore and offshore evolution of the Faial-Pico ridge. The subaerial emergence of this ridge is apparently older than previously thought, i.e., before approximate to 850 ka.Amer Geophysical UnionRCIPLQuartau, RuiMadeira, JFAMitchell, N. C.Tempera, F.Silva, Pedro F.Brandão, F.2016-04-28T10:02:23Z2015-052015-05-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10400.21/6109engQUARTAU, Rui; [et al] - he insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution. Geochemistry Geophysics Geosystems. ISSN 1525-2027. Vol. 16, N.º 5 (2015), pp. 1401-14201525-202710.1002/2015GC005733metadata only accessinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-08-03T09:50:29Zoai:repositorio.ipl.pt:10400.21/6109Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:15:18.564347Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
The insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution |
title |
The insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution |
spellingShingle |
The insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution Quartau, Rui Volcanic ocean island Shelf development Coastal erosion Lava progradation Mass wasting Geological evolution |
title_short |
The insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution |
title_full |
The insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution |
title_fullStr |
The insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution |
title_full_unstemmed |
The insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution |
title_sort |
The insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution |
author |
Quartau, Rui |
author_facet |
Quartau, Rui Madeira, JFA Mitchell, N. C. Tempera, F. Silva, Pedro F. Brandão, F. |
author_role |
author |
author2 |
Madeira, JFA Mitchell, N. C. Tempera, F. Silva, Pedro F. Brandão, F. |
author2_role |
author author author author author |
dc.contributor.none.fl_str_mv |
RCIPL |
dc.contributor.author.fl_str_mv |
Quartau, Rui Madeira, JFA Mitchell, N. C. Tempera, F. Silva, Pedro F. Brandão, F. |
dc.subject.por.fl_str_mv |
Volcanic ocean island Shelf development Coastal erosion Lava progradation Mass wasting Geological evolution |
topic |
Volcanic ocean island Shelf development Coastal erosion Lava progradation Mass wasting Geological evolution |
description |
Shelves surrounding reefless volcanic ocean islands are formed by surf erosion of their slopes during changing sea levels. Posterosional lava flows, if abundant, can cross the coastal cliffs and fill partially or completely the accommodation space left by erosion. In this study, multibeam bathymetry, high-resolution seismic reflection profiles, and sediment samples are used to characterize the morphology of the insular shelves adjacent to Pico Island. The data show offshore fresh lava flow morphologies, as well as an irregular basement beneath shelf sedimentary bodies and reduced shelf width adjacent to older volcanic edifices in Pico. These observations suggest that these shelves have been significantly filled by volcanic progradation and can thus be classified as rejuvenated. Despite the general volcanic infilling of the shelves around Pico, most of their edges are below the depth of the Last Glacial Maximum, revealing that at least parts of the island have subsided after the shelves formed by surf erosion. Prograding lava deltas reached the shelf edge in some areas triggering small slope failures, locally decreasing the shelf width and depth of their edges. These areas can represent a significant risk for the local population; hence, their identification can be useful for hazard assessment and contribute to wiser land use planning. Shelf and subaerial geomorphology, magnetic anomalies and crustal structure data of the two islands were also interpreted to reconstruct the long-term combined onshore and offshore evolution of the Faial-Pico ridge. The subaerial emergence of this ridge is apparently older than previously thought, i.e., before approximate to 850 ka. |
publishDate |
2015 |
dc.date.none.fl_str_mv |
2015-05 2015-05-01T00:00:00Z 2016-04-28T10:02:23Z |
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://hdl.handle.net/10400.21/6109 |
url |
http://hdl.handle.net/10400.21/6109 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
QUARTAU, Rui; [et al] - he insular shelves of the Faial-Pico Ridge (Azores archipelago): a morphological record of its evolution. Geochemistry Geophysics Geosystems. ISSN 1525-2027. Vol. 16, N.º 5 (2015), pp. 1401-1420 1525-2027 10.1002/2015GC005733 |
dc.rights.driver.fl_str_mv |
metadata only access info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
metadata only access |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Amer Geophysical Union |
publisher.none.fl_str_mv |
Amer Geophysical Union |
dc.source.none.fl_str_mv |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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