The Sorbas-Tabernas basin is one of several Neogene basins formed at a late stage in the evolution of the Betic Cordillera, SE Spain. The southern margin of this basin was subsequently inverted and overthrust exposing the complete stratigraphic sequence. Deep-marine deposits deformed by syn-sedimentary tectonics dominate the basin-fill. In the past the basin has been variously interpreted as a pull-apart basin along a strike-slip fault, a flexural basin in front of a thrust, and a rift basin formed during late orogenic extension. It is, however, more appropriate to view this basin as a polyhistory basin due to its complex tectonic history.
Age dates and palaeobathymetric data are attained using a suite of techniques, including strontium isotope stratigraphy, biostratigraphy, and magnetostratigraphy. This data enables the sedimentary succession to be backstripped in order to determine the subsidence history of this basin. The dominant basin forming mechanism has changed through time resulting in a complex subsidence history. By compiling a structural database and using the dating techniques, age constraints have been tentatively placed on periods of subsidence caused by the different basin forming mechanisms.
Results so far suggest that the basin formed rapidly in an extensional (rifting) phase, dominated by NE-SW dipping faults. This phase started in the early Tortonian, terminating in the mid-Tortonian. Subsidence and sediment accumulation continued in a sinistral-oblique strike-slip setting until a later stage compressional event occurred in the latest Tortonian/early Messinian. This resulted in the folding and inversion of this sequence prior to continued Messinian sedimentation.
AAPG Search and Discovery Article #90925©1999 AAPG Foundation Grants-in-Aid