Stratigraphic record and palaeogeographical context of the Neogene basins in the Betic Cordillera, Spain

Abstract

The Betic Cordillera (Southern Spain) acquired its present configuration during the Neogene. The formation, evolution and total or partial destruction of Neogene sedimentary basins were highly controlled by the geodynamic situations and the positions of the basins in the Betic Cordillera. It is impossible to reconstruct the geometry of basins formed during the Early and Middle Miocene, concurrently with the westward drift of the Internal Zones, because in many cases only small outcrops remain. The basins formed on the mobile substratum (the Internal Zones) are characterized by a sedimentary infill made up of synorogenic deposits, which were intensely deformed towards the end of the Middle Miocene, and which were heavily eroded before the beginning of the Late Miocene. In the External Zones, deposition mainly took place in the North Betic Strait, an area across which there was wide communication between the Atlantic and the Mediterranean, which received huge olistostromic masses in its more mobile sector (the foredeep basin), and which evolved differently in its eastern and western sectors. The palaeogeography of the Cordillera changed radically at the beginning of the Late Miocene, when the westward drift of the Internal Zones ceased. During this time the North Betic Strait disappeared and, in what had been its northwestern half approximately, the Guadalquivir Basin became individualized. This basin, which was located between the Betic Chain and the emerged Hercynian Massif, acquired a structure similar to that of the present basin and its extension was also similar to that of the present Neogene outcrops. Intramontane basins became individualized in the recently formed and progressively emerged mountain chain, reaching a development and size in this Cordillera much greater than in other Alpine chains. These basins are characterized by their thick infills, which are unconformable on the folded and deformed substratum, and which can be subdivided according to the different movements of the fault sets that controlled their evolution.

Two Tertiary metamorphic events recognized in high‐pressure metapelites of the Nevado‐Filábride Complex (Betic Cordillera, S Spain)

“…The Alboran domain is considered as a collisional belt that underwent a large-scale gravitational collapse during late orogenic phases, that is contraction was followed by an orogenic extension (Balany a, Garc ıa-Dueñas, Azañ on, & S anchez-G omez, 1997; Garc ıa-Dueñas, Balany a, & Mart ınez-Mart ınez, 1992; Platt et al, 2006). This domain is an allochthonous terrane (Sanz de Galdeano & Vera, 1992) with subducted rocks of thinned continental and oceanic material that originally resided between Eurasia and Africa prior to their convergence. Presently, most of the Albor an domain is believed to be beneath the Alboran Sea (Figure 1a), but its outer margins are exposed along the southern coast of Spain and the northern coast of Morocco (Behr & Platt, 2012;Garc ıa-Dueñas et al, 1992).…”

An exceptionally long paleoseismic record of a slow-moving fault: The Alhama de Murcia fault (Eastern Betic shear zone, Spain)

“…1). In the eastern part of the range, the tectonic exhumation of these complexes during the main postcollisional period gave rise to a series of marine-continental tectono-sedimentary basins (Sanz de Galdeano and Vera, 1992;Rodríguez-Fernández and Sanz de Galdeano, 1992;Montenat , 1996). Most of these basins were bounded by extensional faults.…”

The Torcal de Antequera, an example of a structure formed by a large scale dextral transcurrent system

“…The variation of the stress ellipsoid itself over time is noted in the Betic Cordillera, where the horizontal regional compression shifted in the early and middle Miocene from a WNW-ESE direction to NW-SE, NNW-SSE and even, in some places, to NNE-SSW, now from the late Miocene (Sanz de Galdeano and Vera, 1992;Sanz de Galdeano, 1990;Galindo-Zaldívar et al, 1993).…”