Oligocene to Middle Miocene basin development in the Velez Rubio Corridor - Espuna (Internal-External Zone Boundary; Eastern Betic Cordilleras, SE Spain).

The Velez Rubio Corridor and the area northwest of the Sierra Espuna are located on the Internal-External Zone Boundary. The External Zone is represented by the Southern Subbetic, the most basinward part of the former passive margin of Iberia, the Internal Zone by its unmetamorphosed highest unit, the Malaguide Complex, tectonically underlain by the metamorphosed Alpujarride Complex. During the Oligocene and Aquitanian, the Southern Subbetic was the locus of slope deposition with northeastern provenance of detritus. In the Malaguides of the Espuna, the detritus of Lower Oligocene transgressive conglomerates and Middle Oligocene fan deltas indicates Sardinian proximity. The Upper Oligocene to lower Aquitanian Ciudad Granada and Pliego formations of the Malaguide Complex, carrying exclusively Malaguide detritus, were deposited in grabens within the Malaguide realm during an extensional rifting phase. The Malaguides, still far removed from the Subbetic, underwent major thrusting during the Aquitanian. Of the sedimentary units found between the Internal and External Zones, the oldest unit (the allochthonous Aquitanian Solana formation) was deposited in submarine fans outside the Subbetic or Malaguide realms proper, but in close connection with the latter. The Internal Zone collided with the External Zone in the early Burdigalian with concomitant disruption of the Southern Subbetic slope. On the suture, a deep basin was formed and filled in by the Burdigalian Espejos formation carrying detritus from the Subbetic and from the Malaguide and Alpujarride Complexes. In the late Burdigalian, the Subbetic was thrust southward over the Espejos formation, thus double-sealing the collisional contact. During the latest Burdigalian to Langhian, new basins were formed along the Internal-External Zone Boundary and within the Southern Subbetic. The onset of strike-slip faulting caused shoaling and uplift of these basins. Onset of a new pattern of strike-slip faulting induced the formation of a new suite of basins during the Tortonian, e.g. the Lorca Basin

Oligocene to middle Miocene basin development in the Eastern Betic Cordilleras, SE Spain (Velez Rubio Corridor - Espuna): reflections of west Mediterranean plate-tectonic reorganizations

The suture between two West Mediterranean crustal blocks once situated several hundreds of kilometres apart can be studied in the Velez Rubio Corridor-Espuna area of the Eastern Betic Cordilleras. This suture, or Internal-External Zone Boundary, separates the former passive southern margin of Iberia (the External Zone) from a stack of allochthonous nappe complexes (the Internal Zone), of which the highest unit is formed by the weakly or nonmetamorphosed Malaguide Complex. Analysis of the Oligocene to middle Miocene sediments of the Velez Rubio Corridor and the Espuna, and comparison with coeval deposits elsewhere in the Western Mediterranean shows that (a) up to the middle Miocene, the southern part of the External Zone (Southern Subbetic) was positioned some 100 km more eastward; (b) up to the early Aquitanian, the Malaguide Complex, forming part of the South Sardinian block (the southern section of a West Mediterranean continental segment) was juxtaposed to the North Sardinian block (the northern part of that continental fragment), some 400 km more eastward; (c) West European extensional rifting during the late Oligocene to earliest Aquitanian resulted in deposition of rift valley sediments (Ciudad Granada and Pliego Formations) in the Malaguide realm; (d) during the Aquitanian, the West Mediterranean segment disintegrated and the West Mediterranean oceanic basins opened, resulting in, for example, the south-westward drift of the Internal Zone, with concomitant thrusting and thinning and deposition of submarine fans (Solana-Algeciras Formation) along the margin; (e) in the early Burdigalian, the allochthonous Internal Zone collided with the Iberian margin, causing the disruption of the platform-slope configuration of the External Zone; (f) after the collision a deep basin was formed upon the suture filled in with erosional products from both Internal and External Zones (Espejos-Vinuelas-Millanas Formations); (g) a strong compressive event in the late Burdigalian caused the southward thrusting of the Subbetic over the Espejos Formation, thus double-sealing the collisional contact; (h) in the latest Burdigalian to Langhian, new strongly subsiding basins were formed in the Western Mediterranean, e.g. along the Internal-External Zone boundary; (i) dextral strike-slip faulting in the Serravallian resulted in a westward displacement of over 100 km of the southern Subbetic plus Internal Zone; (j) onset of a new pattern of strike-slip faulting induced the formation of a new suite of basins in the Tortonian