POST-CALABRIAN SEQUENCE STRATIGRAPHY OF THE NORTHWESTERN ALBORAN SEA (SOUTHWESTERN MEDITERRANEAN)

The post-Calabrian sedimentary column of the northwestern Alboran Sea comprises three depositional sequences. The two older depositional seq uences are defined by lowstand systems tracts (shelf-margin deltas, sl ope, base-of-slope, and basin deposits, and the Guadiaro channel-levee complex). In contrast, the most recent depositional sequence also inc ludes transgressive (relict shelf facies) and high-stand (the Guadalme dina-Guadalhorce prodelta and hemipelagic facies) systems tracts. The stratigraphic architecture of these depositional sequences is controll ed by the synchronism between high frequency sea-level changes, variat ions in sediment supply, and sedimentary processes. The configuration of the depositional sequences is variable and their distribution is co mplex, as a result of the relative importance played by sea-level chan ges and tectonism through the area. The sequence boundaries are repres ented by polygenetic surfaces in the proximal margin, and by monogenet ic surfaces in the distal margin and basin. Each polygenetic surface r esults from the interaction between the sequence boundary with the low stand erosional truncation surface and the transgressive surface, both developed during the previous sea-level cycle. The monogenetic surfac es correspond to unconformities and their correlative conformities, fo rmed during sea-level lowstands. This pattern of depositional sequence s developed in the margin and basin of the northwestern Alboran Sea sh ows differences with the Exxon Sequence Stratigraphy Model as traditio nally applied: sea-level change control is essentially recognized thro ugh lowstand systems tracts, and sequence boundary coincides with lows tand erosional truncation surface and transgressive surface, both deve loped during the previous sea-level cycle.