Dinoflagellate Cysts Across the Cretaceous-Palaeogene Boundary from Ouled Haddou, South-Eastern Rif, Morocco

Hamid Slimani¹, Stephen Louwye², and Abdelkabir Toufiq^3
1Laboratory of Geology & Remote sensing, Université Mohammed V-Agdal, Rabat-Agdal, Morocco
²Research Unit Palaeontology, Ghent University, Ghent, Belgium
³Laboratory of Geosciences & Environmental Techniques, University Chouaïb Doukkali, El Jadida, Morocco

A palynological investigation of a recently described and foraminifera-dated section at Ouled Haddou (south-eastern Rifian Corridor) in northern Morocco, revealed rich and well-preserved dinoflagellate cyst assemblages, that enabled a subdivision of Maastrichtian and Danian deposits. The gradual change and the biostratigraphic resolution of these assemblages suggest a complete record of the Cretaceous/Palaeogene transition, which is in agreement with planktonic foraminiferal data. The identification of the Uppermost Maastrichtian and Lowermost Danian intervals is based here on global dinoflagellate cyst events, such as the higher abundance of Manumiella seelandica, the lowest occurrence (LO) of Disphaerogena carposphaeropsis, the highest occurrence (HO) of Dinogymnium spp. and LO of Danian markers as Carpatella cornuta, Damassadinium californicum, Membranilarnacia tenella and Senoniasphaera inornata. The KPg boundary is placed immediately above the peak abundance of M. seelandica and below the LO of D. californicum. The succession of these bioevents allows the recognition of an Uppermost Maastrichtian unnamed zone and the known Lowermost Danian Damassadinium californicum Zone with two subzones A and B. The biostratigraphic interpretations are based here on comparison with known dinoflagellate cyst ranges and zonations in several reference sections and elsewhere in Morocco and other regions. The peridinioid assemblage reported here suggests deposition in a tropical to warm temperate province.

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