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Geodynamic Evolution of the Gibraltar Arc System: First Order Milestones Characterized by Geological Data

Ana Crespo-Blanc, Juan Carlos Balanyá, Menchu Comas, Leticia Barco, Alejandro Jimenez-Bonilla, Manuel Díaz-Azpiroz, Inmaculada Expósito, Enric Suades, and María Luján

The Gibraltar Arc system (GAS), which includes the Betic-Rif orogenic belt, the Alboran and Argelian- Balearic basins and the arcuate accretionary prism present also in the Cadiz Gulf, closes the Alpine-Mediterranean orogenic system to the west. Since at least two decades, the geodynamic evolution of the GAS has been a matter of debate and a huge number of models, so many as working groups, have been proposed. In such type of models, it is necessary to consider the Gibraltar Arc system (GAS) as a whole but it is also essential to avoid oversimplifications, which frequently “dissolve” the geological data.

The updating at a 1:250.000 scale of a geological map of the Betics and its extension offshore, represents an excellent opportunity to put all together the results of twenty years of research of our teams on this natural case-study, mainly with field and marine geology approach. The revision of an extensive bibliography permits us to refresh and characterize first order milestones of the Miocene to Recent geodynamic evolution of the Betic-Cordillera in particular and the GAS in general.

In the GAS, various structural domains coexist, characterized by their specific types of structures and kinematics. With respect to the Miocene to Recent times, they deformed contemporaneously, but with different local tectonic regimes, extensional and/or compressional, and with different displacement gradient. These structural domains end on --or are cut by—transfer zones. The analysis of the structural pattern of each of these domains (superposition of structures, transport direction, boundary conditions, …) let us to establish the relative chronology of the tectonic events that affected them. In turn, the milestones set up for each one of the domains, seen as a whole, allow us to refine and/or validate geodynamic evolution models of the SAG within the Africa-Iberia convergence setting for the considered time interval.

AAPG Search and Discovery Article #90161©2013 AAPG European Regional Conference, Barcelona, Spain, 8-10 April 2013