Biostratigraphic and paleoenvironmental contributions of calcareous nannofossil study from Tortonian-Messinian deposits of Chelif basin (NW Algeria)

• Main Authors: Mansouri, Mohamed El Habib, Bessedik, Mostefa, Aubry, Marie-Pierre, Belkebir, Lahcene, Mansour, Bouhameur, Beaufort, Luc, L
• Other Authors: Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Planktonic foraminifera
• Online Access: https://hal.science/hal-01458320

Special Meeting of the APF on Biodiversity and Biodiversity Crisis in North Africa during Neogene, Paris, FRANCE, NOV 28-29, 2006 International audience Fifty calcareous nannofossil species were listed in the upper Miocene deposits of the Northern Chelif Basin (Dahra, Ben Dourda section). The frequence of some of them (Discoaster loeblichii, D. quinqueramus, Amaurolithus primus and A. amplificus) suggests the presence of four subzones (NN 10a, NN 10b, NN 11b, NN 11 c) which are assigned to the Tortonian and Messinian stages. The NN 11 a subzone is absent (hiatus), testified by the (first) simultaneous occurrence (FO) of D. quinqueramus and A. primus. In the same samples, planktonic foraminifera analysis revealed a comparable succession of biozones (Neogloboquadrina acostaensis, N. humerosa-N. dutertrei and Globorotalia mediterranea) which make possible a good calibration between biostratigraphic scales (calcareous nannofossils, foraminifera). The Tortonian-Messinian boundary is pointed out at the sample 28 of the section and characterized by the first occurrence (FO) of A. delicatus and Reticulo/enestra rotaria on the one hand and G. mediterranea on the other hand. The assemblage analysis and relative abundance fluctuations of Coccolithus pelagicus and R. pseudo-umbilicus show evidence of seven successive phases which are characterized, alternately, by cold and hot water marine masses, light intensity variations and nutrient availability.