NEOGENE SEDIMENTATION AND TECTONIC-EUSTATIC CONTROL OF THE MALAGA BASIN, SOUTH SPAIN

Cenozoic sediments in the Malaga area range from the lower Miocene or uppermost Oligocene to the Quaternatry. Tortoniun (lute Miocene) - Quaternary sediments correspond to the fill of the Malaga Basin. Older sediments were laid down before the basin had. acquired its present-day structure. A number of important stratigraphic discontinuities are present within the Cenozoic succession. In the lute Oligocene-early Miocene, sandy sediments and conglomerates assigned to the Alozaina Formation, d.erived from the basement Malaguide Complex, were deposited in shallow-marine conditions contemporaneously with deformation in the Internal Zones of the Belie Cordillera. The overlying transgressive Vinuela Formation (late Aquitanianearly burdigalian) was deposited in deep-marine conditions which extended, over a somewhat wider area than that occupied by the Malaga Basin. Sedimentation wa.s dominated by classical turbidity currentsʹ and high-density mass flows. Sediments of middle Miocene age are absent. Marine sedimentation, resumed in the 1ʹortonian as a consequence of a eustatic sea-level rise. There was clear tectonic contra! on the depositional system as indicated both by the occurrence of coarse-grained detritic sediments, which impeded the development of a bioclastic (carbonate) shelf, and also by the formation of a prominent unconformity. NW-SE and NE-SW Irending faults, defining subsiding areas and highs, controlled the pattern of sedimentation. Strike-slip activity on these faults (right- and left-lateral, respectively) was relatively minor compared to dip-slip activity; normal faults with throws of up to 1km are known, and result from approximately east-west extension. The Tortonian succession is overlain unconformably by Pliocene marine deposits which were deposited during an abrupt transgression. Post-Pliocene sedimentation has been largely continental.