Seismic analysis of the southern margin of the Alboran Sea

Abstract

This study is based on a structural and sedimentary analysis of high resolution seismic profiles carried out on the southern margin of the Alboran sea. In the eastern area, recent tectonic movements have strongly affected the deposits. The Alboran Ridge was structured in a complex antiform at the end of the Pliocene; its present disposition, in horst and subsiding trough structures with a thick infilling, is the result of Quaternary to Recent recurrent faulting. In the western area, near Gibraltar Strait, alternate stages of erosion and construction are apparent in the sequences of the marginal plateau, particularly in the northern part, which progrades towards the Strait. Hydrodynamic patterns and glacio-eustatic variations of sea level have played a prominent role in the genesis of sedimentary bodies. Neither sedimentation nor tectonics seem to indicate a general Miocene-Pliocene boundary but the Pliocene-Quaternary transition is marked, on the ridge and marginal areas, by a major discontinuity; it can be correlated with onshore neotectonic data.