Biostratigraphie et lithologie des séries serravallo-tortoniennes du massif du Dahra et du bassin du Chélif (Algérie). Implications sur la position de la limite serravallo-tortonienne

Lahcene BELKEBIR, Amel LABDI, Bouhameur MANSOUR, Mostefa BESSEDIK & Jean-Paul SAINT MARTIN

fr Geodiversitas 30 (1) - Pages 9-19

Published on 28 March 2008

Biostratigraphic and lithologic Serravallian-Tortonian series of Dahra moutain and the Chelif basin (Algeria). Serravallo-tortonian boundary implication.

A lithological and biostratigraphical study was carried out on the Djebel Meni section (Dahra Mountain, Algeria) based upon 54 samples. According to the distribution of the main planktonic foraminifera species index we identified two subzones (Orbulina suturalis, O. universa) attributed respectively to the Upper Langhian and Lower Serravallian stages and two biozones (Neogloboquadrina acostaensis, N. humerosa-N. dutertrei) indicating a Tortonian age. These new data allow to reconsider the previous chronostratigraphic attributions and to point out the absence of the Upper Serravallian and of the base of the Tortonian. The transition features between the Serravallian and Tortonian deposits are better identified by comparisons with northern and southern margins of the Chelif basin. The precise age of the Tortonian transgression is specified.

Keywords :

boundary, planktonic foraminifera, lithology, biostratigraphy, Djebel Meni, Chelif basin, Algeria

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