Role of an extension of pre-Quaternary age for the evolution of the carbonate massifs in the occidental Betic Cordillera; the case of the Yunquera-Nieves Massif (southern Spain)

A simultaneous analysis of the fracture geometry and paleo-stress fields of the karstic Yunquera-Nieves massif in southern Spain (Malaga Province) has been carried out with microtectonic stations. It reveals polyphased tectonics linked to the structural position of this carbonate domain in the western Betic Cordillera. Among the tectonic regimes described in this domain appears a distensive stage with a radial trend probably of post-Tortonian to Quaternary age. Todate, it has seldom been described and is absent from geodynamic models though it seems to have had a regional importance. Furthermore, it played a major role for the acquisition of the hydrodynamic properties of the aquifer and its karstogenesis. This stage opened all fractures and allowed the development of karstic drains with NW-SE and N-S directions. Finally, the karstic network was shaped by more recent climatic and tectonic events.