Morphology of the last subaerial unconformity on a shelf : insights into transgressive ravinement and incised valley occurrence in the Gulf of Cádiz
The main aim of this study is to explore the spatial patterns of the shelf-scale erosional unconformity related to the last glacial maximum (LGM), particularly in terms of the role of underlying geology and the presumed primary influence of sea-level changes. This involved a detailed mapping of the...
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2018
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ftunivgent:oai:archive.ugent.be:8548753 2023-06-11T04:15:18+02:00 Morphology of the last subaerial unconformity on a shelf : insights into transgressive ravinement and incised valley occurrence in the Gulf of Cádiz Lobo, FJ García, M Luján, M Mendes, I Reguera, MI Van Rooij, David 2018 application/pdf https://biblio.ugent.be/publication/8548753 http://hdl.handle.net/1854/LU-8548753 https://doi.org/10.1007/s00367-017-0511-9 https://biblio.ugent.be/publication/8548753/file/8548757 eng eng https://biblio.ugent.be/publication/8548753 http://hdl.handle.net/1854/LU-8548753 http://dx.doi.org/10.1007/s00367-017-0511-9 https://biblio.ugent.be/publication/8548753/file/8548757 No license (in copyright) info:eu-repo/semantics/restrictedAccess GEO-MARINE LETTERS ISSN: 0276-0460 ISSN: 1432-1157 Earth and Environmental Sciences RESOLUTION SEQUENCE STRATIGRAPHY JERSEY OUTER SHELF SEA-LEVEL RISE CONTINENTAL-SHELF LATE QUATERNARY POSTGLACIAL TRANSGRESSION SEISMIC STRATIGRAPHY NORTHERN GULF HOLOCENE SYSTEMS journalArticle info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2018 ftunivgent https://doi.org/10.1007/s00367-017-0511-9 2023-05-10T22:26:53Z The main aim of this study is to explore the spatial patterns of the shelf-scale erosional unconformity related to the last glacial maximum (LGM), particularly in terms of the role of underlying geology and the presumed primary influence of sea-level changes. This involved a detailed mapping of the most recent and widespread erosional shelf surface in a sector of the northern margin of the Gulf of Cadiz (northeast Atlantic Ocean) located adjacent to a major fluvial source. A dense network of high-resolution seismic profiles collected in the 1990s and 2013 off the Guadiana River revealed two distinct geomorphological domains on the LGM shelf-scale subaerial surface. The outer domain exhibits a widespread occurrence of erosional truncations, with a rugged, erosional pattern over the most distal shelf setting that evolves landward into a planar unconformity. The inner domain is more extensive and is characterized by the common occurrence of highly reflective, localized mounded seismic facies that laterally evolve into an irregular surface and in places may develop a channelized morphology. Significant fluvial incision is limited to a major straight valley and a secondary distributary channel. A distinct partition of the lowstand surface is documented, and attributed to a well-marked lithological change. A coarse-grained inner shelf comprises underlying lithified coastal deposits, whereas a fine-grained outer shelf is regarded as the uppermost expression of regressive prodeltaic wedges. The influence of regional indurated surfaces is also expressed in (1) the pattern of erosion, this being more patchy on the inner shelf due to lateral changes of erodibility, whereas on the outer shelf it shows laterally continuous bands, owing to different modes of transgressive ravinement; (2) the spatial and temporal variability of fluvial incision. Inner shelf armoring by indurated deposits prevents reoccupation of previously incised valleys. Article in Journal/Newspaper Northeast Atlantic Ghent University Academic Bibliography Geo-Marine Letters 38 1 33 45 |
institution |
Open Polar |
collection |
Ghent University Academic Bibliography |
op_collection_id |
ftunivgent |
language |
English |
topic |
Earth and Environmental Sciences RESOLUTION SEQUENCE STRATIGRAPHY JERSEY OUTER SHELF SEA-LEVEL RISE CONTINENTAL-SHELF LATE QUATERNARY POSTGLACIAL TRANSGRESSION SEISMIC STRATIGRAPHY NORTHERN GULF HOLOCENE SYSTEMS |
spellingShingle |
Earth and Environmental Sciences RESOLUTION SEQUENCE STRATIGRAPHY JERSEY OUTER SHELF SEA-LEVEL RISE CONTINENTAL-SHELF LATE QUATERNARY POSTGLACIAL TRANSGRESSION SEISMIC STRATIGRAPHY NORTHERN GULF HOLOCENE SYSTEMS Lobo, FJ García, M Luján, M Mendes, I Reguera, MI Van Rooij, David Morphology of the last subaerial unconformity on a shelf : insights into transgressive ravinement and incised valley occurrence in the Gulf of Cádiz |
topic_facet |
Earth and Environmental Sciences RESOLUTION SEQUENCE STRATIGRAPHY JERSEY OUTER SHELF SEA-LEVEL RISE CONTINENTAL-SHELF LATE QUATERNARY POSTGLACIAL TRANSGRESSION SEISMIC STRATIGRAPHY NORTHERN GULF HOLOCENE SYSTEMS |
description |
The main aim of this study is to explore the spatial patterns of the shelf-scale erosional unconformity related to the last glacial maximum (LGM), particularly in terms of the role of underlying geology and the presumed primary influence of sea-level changes. This involved a detailed mapping of the most recent and widespread erosional shelf surface in a sector of the northern margin of the Gulf of Cadiz (northeast Atlantic Ocean) located adjacent to a major fluvial source. A dense network of high-resolution seismic profiles collected in the 1990s and 2013 off the Guadiana River revealed two distinct geomorphological domains on the LGM shelf-scale subaerial surface. The outer domain exhibits a widespread occurrence of erosional truncations, with a rugged, erosional pattern over the most distal shelf setting that evolves landward into a planar unconformity. The inner domain is more extensive and is characterized by the common occurrence of highly reflective, localized mounded seismic facies that laterally evolve into an irregular surface and in places may develop a channelized morphology. Significant fluvial incision is limited to a major straight valley and a secondary distributary channel. A distinct partition of the lowstand surface is documented, and attributed to a well-marked lithological change. A coarse-grained inner shelf comprises underlying lithified coastal deposits, whereas a fine-grained outer shelf is regarded as the uppermost expression of regressive prodeltaic wedges. The influence of regional indurated surfaces is also expressed in (1) the pattern of erosion, this being more patchy on the inner shelf due to lateral changes of erodibility, whereas on the outer shelf it shows laterally continuous bands, owing to different modes of transgressive ravinement; (2) the spatial and temporal variability of fluvial incision. Inner shelf armoring by indurated deposits prevents reoccupation of previously incised valleys. |
format |
Article in Journal/Newspaper |
author |
Lobo, FJ García, M Luján, M Mendes, I Reguera, MI Van Rooij, David |
author_facet |
Lobo, FJ García, M Luján, M Mendes, I Reguera, MI Van Rooij, David |
author_sort |
Lobo, FJ |
title |
Morphology of the last subaerial unconformity on a shelf : insights into transgressive ravinement and incised valley occurrence in the Gulf of Cádiz |
title_short |
Morphology of the last subaerial unconformity on a shelf : insights into transgressive ravinement and incised valley occurrence in the Gulf of Cádiz |
title_full |
Morphology of the last subaerial unconformity on a shelf : insights into transgressive ravinement and incised valley occurrence in the Gulf of Cádiz |
title_fullStr |
Morphology of the last subaerial unconformity on a shelf : insights into transgressive ravinement and incised valley occurrence in the Gulf of Cádiz |
title_full_unstemmed |
Morphology of the last subaerial unconformity on a shelf : insights into transgressive ravinement and incised valley occurrence in the Gulf of Cádiz |
title_sort |
morphology of the last subaerial unconformity on a shelf : insights into transgressive ravinement and incised valley occurrence in the gulf of cádiz |
publishDate |
2018 |
url |
https://biblio.ugent.be/publication/8548753 http://hdl.handle.net/1854/LU-8548753 https://doi.org/10.1007/s00367-017-0511-9 https://biblio.ugent.be/publication/8548753/file/8548757 |
genre |
Northeast Atlantic |
genre_facet |
Northeast Atlantic |
op_source |
GEO-MARINE LETTERS ISSN: 0276-0460 ISSN: 1432-1157 |
op_relation |
https://biblio.ugent.be/publication/8548753 http://hdl.handle.net/1854/LU-8548753 http://dx.doi.org/10.1007/s00367-017-0511-9 https://biblio.ugent.be/publication/8548753/file/8548757 |
op_rights |
No license (in copyright) info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1007/s00367-017-0511-9 |
container_title |
Geo-Marine Letters |
container_volume |
38 |
container_issue |
1 |
container_start_page |
33 |
op_container_end_page |
45 |
_version_ |
1768371996434890752 |