Rôle des microbialites et des « micro-encroûtants » dans la lithification récifale : exemples du Jurassique supérieur de l'Atlas maghrébin (Maroc et Tunisie)

Abstract

In the Upper Jurassic, reefs from the Maghrebian Atlas, inter- and intraskeletal cavities were infilled by microbialites associated with microencrusters: Bacinella irregularis, Tubiphytes obscurus, Lithocodium aggregatum and encrusting forams. Microbialitic activity was the main lithifying agent in the reef framework both in the Tethysian and Atlantic buildups of the Maghreb Atlas. They occupied about 20 % of the whole biomass volume in the Oxfordian reef, 40 % in the Kimmeridgian reef (High Atlas, Morocco) and 25 % in the Tithonian bioherm (Tunisia).