Decoding the paleoceanography of the Alboran Sea through contourites

Abstract

The cross-disciplinary fields including geomorphology, sedimentology and physical oceanography have highlighted the governance of the water masses on the sedimentation of the margins and basins of the Alboran Sea during the Pliocene and Quaternary. The results obtained from analyzing the intricate relationship between the sedimentary processes and the action of the light and dense Mediterranean waters (MW) has been transferred to the paleosurfaces of the main stratigraphic divisions. This has allowed us to define multiple Contourite Depositional Systems, dominated by a great variety of depositional and erosive features. Their seismic facies as well as their temporal and spatial variability suggest the action of low dense and high dense MW since the beginning of the Pliocene, and have allowed decoding the paleocirculation, that involves significant relocation of main flow pathways, both longitudinal and transversal. We have inferred three circulation models: 1) during the infilling of the Mediterranean basin, highly erosive; 2) during the Pliocene a strong countercurrent eroded the Spanish base of slope, comprising two stages: 2a) Lower Pliocene, the Western and Southern basins were connected allowing the circulation of high dense waters; 2b) Upper Pliocene, the uplift of the SW section of the Alboran Ridge interrupts the connection; and 3) the Quaternary model is similar to the present day, characterized by an enhanced density contrast between the low and high dense MW and a less energetic recirculation. These stages reflect variability in the bottom-current regimes and related along-slope efficiency in transport, deposition and erosion