The role of extensional detachment systems in thinning the crust and exhuming granulites: analogies between the offshore Le Danois High and the onshore Labourd Massif in the Biscay/Pyrenean rifts

Large uncertainties remain about the architecture, timing and role of the structures responsible for high degrees of crustal thinning and the exhumation of mid-crustal granulites in the Pyrenean and Biscay rift systems. Both, the Le Danois High in the North Iberian margin and the Labourd Massif in t...

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Autores principales:	Cadenas Patricia, Lescoutre Rodolphe, Manatschal Gianreto, Fernández-Viejo Gabriela
Formato:	article
Lenguaje:	EN FR
Publicado:	EDP Sciences 2021
Materias:	extensional detachment system crustal thinning exhumation granulite rift segmentation bay of biscay/pyrenees Geology QE1-996.5
Acceso en línea:	https://doaj.org/article/82dd22f150a743ea863aac5e1900fe18
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spelling	oai:doaj.org-article:82dd22f150a743ea863aac5e1900fe182021-12-02T17:11:12ZThe role of extensional detachment systems in thinning the crust and exhuming granulites: analogies between the offshore Le Danois High and the onshore Labourd Massif in the Biscay/Pyrenean rifts1777-581710.1051/bsgf/2021045https://doaj.org/article/82dd22f150a743ea863aac5e1900fe182021-01-01T00:00:00Zhttps://www.bsgf.fr/articles/bsgf/full_html/2021/01/bsgf210007/bsgf210007.htmlhttps://doaj.org/toc/1777-5817Large uncertainties remain about the architecture, timing and role of the structures responsible for high degrees of crustal thinning and the exhumation of mid-crustal granulites in the Pyrenean and Biscay rift systems. Both, the Le Danois High in the North Iberian margin and the Labourd Massif in the Western Pyrenees preserve evidence of extensional detachment faults and include exhumed granulites, which are locally reworked in syn-rift sediments. In this study, we compare the crustal structure and its link to the overlying sediments at the two sites based on the interpretation of high quality 2D seismic reflection profiles offshore and field observations and published geological cross-sections onshore. New reported seismic and field observations support that extensional detachment systems delineate the top basement in the Le Danois High and the Labourd Massif, advocating for a similar tectonic evolution. We propose that the Le Danois and North Mauléon extensional detachment systems were responsible for high degrees of crustal thinning and the exhumation of the pre-rift brittle-ductile transition and associated mid-crustal granulites during Aptian to Cenomanian extension, leading to the formation of the Le Danois and Labourd crustal tapers. Subsequently tilted and uplifted during the Alpine convergence, the two taper blocks lay at present in the hanging-wall of major Alpine thrusts. Their position at overlapping, en-echelon hyperextended rift segments at the end of rifting, and the occurrence of shortcutting structures at depth linking neighbouring rift segments can explain the preservation of the rift-related detachment systems. This study proposes for the first time analogies between the offshore Le Danois High and the onshore Labourd Massif and demonstrates the importance of extensional detachment systems in thinning the crust and exhuming mid-crustal granulites at the seafloor in the Biscay and Pyrenean rift systems during Aptian to Cenomanian extension.Cadenas PatriciaLescoutre RodolpheManatschal GianretoFernández-Viejo GabrielaEDP Sciencesarticleextensional detachment systemcrustal thinningexhumationgranuliterift segmentationbay of biscay/pyreneesGeologyQE1-996.5ENFRBSGF - Earth Sciences Bulletin, Vol 192, p 57 (2021)
institution	DOAJ
collection	DOAJ
language	EN FR
topic	extensional detachment system crustal thinning exhumation granulite rift segmentation bay of biscay/pyrenees Geology QE1-996.5
spellingShingle	extensional detachment system crustal thinning exhumation granulite rift segmentation bay of biscay/pyrenees Geology QE1-996.5 Cadenas Patricia Lescoutre Rodolphe Manatschal Gianreto Fernández-Viejo Gabriela The role of extensional detachment systems in thinning the crust and exhuming granulites: analogies between the offshore Le Danois High and the onshore Labourd Massif in the Biscay/Pyrenean rifts
description	Large uncertainties remain about the architecture, timing and role of the structures responsible for high degrees of crustal thinning and the exhumation of mid-crustal granulites in the Pyrenean and Biscay rift systems. Both, the Le Danois High in the North Iberian margin and the Labourd Massif in the Western Pyrenees preserve evidence of extensional detachment faults and include exhumed granulites, which are locally reworked in syn-rift sediments. In this study, we compare the crustal structure and its link to the overlying sediments at the two sites based on the interpretation of high quality 2D seismic reflection profiles offshore and field observations and published geological cross-sections onshore. New reported seismic and field observations support that extensional detachment systems delineate the top basement in the Le Danois High and the Labourd Massif, advocating for a similar tectonic evolution. We propose that the Le Danois and North Mauléon extensional detachment systems were responsible for high degrees of crustal thinning and the exhumation of the pre-rift brittle-ductile transition and associated mid-crustal granulites during Aptian to Cenomanian extension, leading to the formation of the Le Danois and Labourd crustal tapers. Subsequently tilted and uplifted during the Alpine convergence, the two taper blocks lay at present in the hanging-wall of major Alpine thrusts. Their position at overlapping, en-echelon hyperextended rift segments at the end of rifting, and the occurrence of shortcutting structures at depth linking neighbouring rift segments can explain the preservation of the rift-related detachment systems. This study proposes for the first time analogies between the offshore Le Danois High and the onshore Labourd Massif and demonstrates the importance of extensional detachment systems in thinning the crust and exhuming mid-crustal granulites at the seafloor in the Biscay and Pyrenean rift systems during Aptian to Cenomanian extension.
format	article
author	Cadenas Patricia Lescoutre Rodolphe Manatschal Gianreto Fernández-Viejo Gabriela
author_facet	Cadenas Patricia Lescoutre Rodolphe Manatschal Gianreto Fernández-Viejo Gabriela
author_sort	Cadenas Patricia
title	The role of extensional detachment systems in thinning the crust and exhuming granulites: analogies between the offshore Le Danois High and the onshore Labourd Massif in the Biscay/Pyrenean rifts
title_short	The role of extensional detachment systems in thinning the crust and exhuming granulites: analogies between the offshore Le Danois High and the onshore Labourd Massif in the Biscay/Pyrenean rifts
title_full	The role of extensional detachment systems in thinning the crust and exhuming granulites: analogies between the offshore Le Danois High and the onshore Labourd Massif in the Biscay/Pyrenean rifts
title_fullStr	The role of extensional detachment systems in thinning the crust and exhuming granulites: analogies between the offshore Le Danois High and the onshore Labourd Massif in the Biscay/Pyrenean rifts
title_full_unstemmed	The role of extensional detachment systems in thinning the crust and exhuming granulites: analogies between the offshore Le Danois High and the onshore Labourd Massif in the Biscay/Pyrenean rifts
title_sort	role of extensional detachment systems in thinning the crust and exhuming granulites: analogies between the offshore le danois high and the onshore labourd massif in the biscay/pyrenean rifts
publisher	EDP Sciences
publishDate	2021
url	https://doaj.org/article/82dd22f150a743ea863aac5e1900fe18
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The role of extensional detachment systems in thinning the crust and exhuming granulites: analogies between the offshore Le Danois High and the onshore Labourd Massif in the Biscay/Pyrenean rifts

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