English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/71995
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:


The Gibraltar subduction: A decade of new geophysical data

AuthorsGutscher, Marc-André; Dominguez, Stephane; Westbrook, Graham K.; Le Roy, Pascal; Rosas, Filipe; Duarte, João C.; Terrinha, Pedro; Miranda, J. M.; Graindorge, David; Gailler, Audrey; Sallarès, Valentí ; Bartolomé, Rafael
Roll-back subduction
Tethys oceanic lithosphere
Accretionary wedge
Active deformation
Issue DateOct-2012
CitationTectonophysics 574-575: 72-91 (2012)
AbstractThe Gibraltar arc, spans a complex portion of the Africa–Eurasia plate boundary marked by slow oblique convergence and intermediate and deep focus seismicity. The seemingly contradictory observations of a young extensional marine basin surrounded by an arcuate fold-and-thrust belt, have led to competing geodynamic models (delamination and subduction). Geophysical data acquired in the past decade provide a test for these models and support a narrow east-dipping, subduction zone. Seismic refraction studies indicate oceanic crust below the western Gulf of Cadiz. Tomography of the upper mantle reveals a steep, east-dipping high P-wave velocity body, beneath Gibraltar. The anisotropic mantle fabric from SKS splitting shows arc-parallel “fast directions”, consistent with toroidal flow around a narrow, westward retreating subducting slab. The accompanying WSW advance of the Rif–Betic mountain belt has constructed a thick pile of deformed sediments, an accretionary wedge, characterized by west-vergent thrust anticlines. Bathymetric swath‐mapping images an asymmetric embayment at the deformation front where a 2 km high basement ridge has collided. Subduction has slowed significantly since 5 Ma, but deformation of recent sediments and abundant mud volcanoes suggest ongoing activity in the accretionary wedge. Three possible origins for this deformation are discussed; gravitational spreading, overall NW–SE convergence between Africa and Iberia and finally a WSW tectonic push from slow, but ongoing roll-back subduction. In the absence of arc volcanism and shallow dipping thrust type earthquakes, evidence in favor of present-day subduction can only be indirect and remains the object of debate. Continued activity of the subduction offers a possible explanation for great (M > 8.5) earthquakes known to affect the area, like the famous 1755 Great Lisbon earthquake. Recent GPS studies show SW motion of stations in N Morocco at velocities of 3–6 mm/yr indicating the presence of an independent block, a “Rif–Betic–Alboran” microplate, situated between Iberia and Africa
DescriptionReview article.-- 20 pages, 18 figures
Publisher version (URL)http://dx.doi.org/10.1016/j.tecto.2012.08.038
Appears in Collections:(UTM) Artículos
Files in This Item:
There are no files associated with this item.
Show full item record
Review this work

Related articles:

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.