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, Malavieille, Jacques, Silva, Sónia, Matias, Luis
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2011
• Subjects: North East Atlantic
• Online Access: https://oceanrep.geomar.de/id/eprint/27143/; https://oceanrep.geomar.de/id/eprint/27143/1/1-s2.0-S0025322711002027-main.pdf; https://doi.org/10.1016/j.margeo.2011.09.014

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 similar to 1.8 Ma); ii) subsequent reactivation of these basement faults with dextral strike-slip motion (similar to 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