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, Rosas, Filipe, Terrinha, Pedro, Gutscher, Marc-André, Malavielle, Jacques, Silva, Sonia, Matias, Luis
• Other Authors: Instituto Dom Luiz, Universidade de Lisboa (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; geo; envir; North East Atlantic
• Online Access: https://doi.org/10.1016/j.margeo.2011.09.014; https://hal-insu.archives-ouvertes.fr/insu-00643630/file/Duarte_etal_2011_MS-1.pdf; https://hal-insu.archives-ouvertes.fr/insu-00643630

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.