Les foraminifères "benthiques" de la limite Lias moyen - Lias supérieur dans les rides sud-rifaines (Maroc). Biostratigraphie et considérations paléobiogéographiques

Within the South rifan Heights Basin, northwestern part of the african margin, to the remotest parts of the atlantic-mesogean area, the Middle to Upper Lias boundary must be taken into account for biostratigraphical and paleogeographical analysis (using Ammonite faunas). Foraminiferal studies point out major microfaunale renewal taking place into the Polymorphum zone (= Tenuiscostatum zone). Main species are closely related to european ones. They occur later in the studied area, via the Protoatlantic ocean . This event agrees with the sinking oftheSouth rifan Platform and its evolution to basin.