The present work aims at the realization of a biostratigraphic study based on planktonic foraminifera associations to the transition between the middle Eocene (Bartonian) and late Eocene (Priabonian) in the section of Ben Attya (BAT).
This outcrop is flush in pelagic deposits of external Rif. The lithological point of view, the base of the section consists mainly of calcareous clay with flint sandstone intercalated with marl. Its upper part shows gray marl overlying limestone cement sandstone. The micropaleontological study to recognize associations of planktonic foraminifera characteristic of the Middle and Upper Eocene.
The Middle Eocene (Bartonian) is characterized by the association of species Acarinina pseudotopilensis, Acarinina topilensis, Acarinina spinoinflata, Acarinina bullbrooki, Truncorotaloides libyaensis, Turborotalia frontosa, Morozovella lehneri, Morozovella crassata, Orbulinoides beckmanni, Hantkenina dumblei, Turborotalia boweri, Hastigerina cf. bolivariana and Hantkenina liebusi. The Upper Eocene (Priabonian) is highlighted by the presence of species Globigerinatheka semiinvoluta, Hantkenina alabamensis, Globigerinatheka tropicalis, Turborotalia cerroazulensis, Turborotalia cocoaensis, Turborotalia cunialensis and cribrohantkenina inflata.
Over the entire range studied, five (5) expansion biozones have been recognized. The biozones Morozovella lehneri, Orbulinoides beckmanni and Morozovella crassata are characteristic of Bartonian. The biozone Globigerinatheka semiinvoluta covers the transition from Bartonian and Priabonian. The last biozone (at Globigerinatheka index) corresponds to the lower part of Priabonian.