The late Messinian erosional surface and the subsequent reflooding in the Mediterranean: New insights from the Melilla–Nador basin (Morocco)
Résumé
New field investigations in the Cape des Trois Fourches peninsula (northern Morocco) allow us to bring new insights on the late Messinian erosional surface and the overlying marine deposits. Our results show that the late Messinian erosional surface, characterized by an erosional plateau, is interrupted by an up to 70 m deep paleovalley, thought to result from a landslide. The minimum relative sea-level drop is 70 m, probably much more with regard to the indication that a large-scale landsliding has occurred. The post-erosional deposits (Cycle 3) comprise one major depositional sequence composed of two high-order sedimentary subcycles. Deposits of the first subcycle 3A filled in the erosional basin and the paleovalleys; deposits of the second subcycle 3B overflowed the paleovalleys and the erosional plateau. We found evidence of the transgressive systems tract of the deposits corresponding to the post-Messinian crisis reflooding, for which a latest Messinian onset can neither be proved nor entirely ruled out because the rare biostratigraphic data are not sufficiently conclusive. The uppermost part of the reflooding deposits (subcycle 3A) is shown to be definitely Pliocene in age based on the occurrence of Globorotalia puncticulata and the composition of the assemblage of pectinids.