Thrust-wrench interference tectonics in the Gulf of Cadiz (Africa-Iberia plate boundary in the North-East Atlantic): Insights from analog models

• Published in: Marine Geology
• Main Authors: Duarte, João, C., Rosas, Filipe, M., Terrinha, Pedro, Gutscher, Marc-André, M-A, Malavielle, Jacques, Silva, Sonia, Matias, Luis
• Other Authors: Instituto Dom Luiz, Universidade de Lisboa = University of Lisbon = Université de Lisbonne (ULISBOA), Centro de Geologia Lisboa, LNEG, Unidade de Geologia Marinha, School of Geosciences, Monash University Clayton, Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Géosciences Montpellier, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Faculdade de Ciencias
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: SWIM wrench system; Gulf of Cadiz Accretionary Wedge (GCAW); thrust-wrench interference; analog modeling; Tethyan-related plate boundary; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; [SDE.MCG]Environmental Sciences/Global Changes; North East Atlantic
• Online Access: https://insu.hal.science/insu-00643630; https://insu.hal.science/insu-00643630/document; https://insu.hal.science/insu-00643630/file/Duarte_etal_2011_MS-1.pdf; https://doi.org/10.1016/j.margeo.2011.09.014

International audience In the Gulf of Cadiz key segment of the Africa-Iberia plate boundary (North-East Atlantic ocean), three main different modes of tectonic interference between a recently identified wrench system (SWIM) and the Gulf of Cadiz Accretionary Wedge (GCAW) were tested through analog sand-box modeling: a) An active accretionary wedge on top of a pre-existent inactive basement fault; b) An active strike-slip fault cutting a previously formed, inactive, accretionary wedge; and c) Simultaneous activity of both the accretionary wedge and the strike-slip fault. The results we obtained and the comparison with the natural deformation pattern favor a tectonic evolution comprising two main steps: i) the formation of the Gulf of Cadiz Accretionary Wedge on top of inactive, Tethyan-related, basement faults (Middle Miocene to ~ 1.8 Ma); ii) subsequent reactivation of these basement faults with dextral strike-slip motion (~ 1.8 Ma to present) simultaneously with continued tectonic accretion in the GCAW. These results exclude the possibility of ongoing active SWIM wrench system cross-cutting an inactive GCAW structure. Our results also support a new interpretation of the SWIM wrench system as fundamentally resulting from strike-slip reactivation of an old (Tethyan-related) plate boundary.