Le Passage Paléocène-eocène Dans Les Formations Marines De La Région De Tébessa Ne Algérien (atlas Saharien Oriental) : Étude Des Réponses Géochimiques

Résumé: This study aims to track the petrographic and geochemical evolution during the Paleocene-Eocene transition from the Eastern Saharan Atlas. Tow outcropping sections are selected at Tébessa area (NE Algeria) including Djebel El Kouif and Djebel Dyr sections. The petrographic evolution was performed by the interpretation of thin sections, while the geochemical study has targeted the evaluation geochemical signal using elemental ratios on major elements, trace and rare earth elements to characterize the paleo-redox; paleo-productivity and the terrestrial inputs contributions during the Paleocene-Eocene span time. The results allow tracking the vertical evolution of the depositional environments which was from a deep to shallow environment with a tendency to emersion in the Djebel Dyr (the occurrence of gypsum rocks). The geochemical evolution using trace elements such as vanadium (V); copper (Cu); zirconium (Zr); Nickel (Ni), and the rare earth elements (Ce), has evidenced some conditions related to Paleocene-Eocene Thermal Maximum (PETM); ETM2; ETM3). These results are very important for phosphate dating and need to be confirmed using the isotopes (carbon 13 (13C) and oxygen 18(18O)) and Total Organic Carbon (TOC).

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