Environnements sédimentaires de la Saoura-Ougarta (Sahara Nord-Ouest, Algérie) au Dévonien inférieur (Lochkovien supérieur pro parte-Emsien)

ABSTRACT Lower Devonian (Lochkovian pro parte-Emsian) sedimentary environments of the Saoura-Ougarta (North-Western Sahara, Algeria). The lower Devonian (Upper Lochkovien to Emsian) rocks of the Saoura-Ougarta offers an example of mud-dominated platform with sandstone and limestone tempestites (Dkhissa Formation) bearing benthic fauna, and shales-sandstones beds with limestone episodes (Teferguenite Formation). The facies successions show retrogradational and progradational trends with an evolution from the offshore transition to shoreface (lower member) and from offshore transition to foreshore (upper member) with some carbonate intercalations with SCS structures and stromatolithic crusts. At the base of the Teferguenite Formation, the limestone episodes (A, B and C bars) reflect brutal change of the environmental conditions with sedimentation on carbonate ramp, in its mid position, interfingering with siliciclastics phases. They represent, in the Saoura-Ougarta, rapid transgressive episodes alternating ...