Paper Title
Biodiversity and Paleoenvironmental Distribution of Benthic Foraminifera During The Basal Lias-Dogger In The Aïn Ouarka Area (The Western Saharan Atlas)

Abstract
In this work which relates to the study of benthic Foraminifera, taken in theseries marno-limestones, which level in the Chémarikh cut and that of El Hammam,wewereinterested to followtheir space-timeevolution. The exploitation of the micropaleontologic data made it possible to highlight acuttingbiostratigraphiccomposedoffourassociationsofForaminifera,largelydominatedbyNodosariidae.TheseassociationsfollowoneanothersincelowerLiastothebasal Dogger. Theanalysisofthespace-timedistributionandthebiodiversityofForaminiferamadeitpossibletohighlightseveralpledgedassemblagesthreepaléoenvironnements different, which are distributed as follows: An external plat form medium, which is characterized by the importance of the argillaceous contributions and in which No dosariidae are abundant. They are associated with Spirillinidae and with Bolivinitidae; a second relatively major medium of slope, ensuring the transitionenters the platform and the basin. In this medium, Foraminifera are represented byNodosariidaeand Spirillinidae, associated with the appearance of the first forms ofPolymorphinidaeandCératobuliminidae.Thepercentageoftheselastformsisreduced.Thethirdmediumcorrespondstothebasinandtheverymajorzone.Thislast east medium creates during the distensive tectonic differentiation of Lias. It is characterized by the prevalence of Nodosariidae to which come to be strongly addedindicatingformsofdepthsuchasPolymorphinidae,CératobuliminidaeandGlobuligirinidae. The comparative study between the two cuts Chemarikh and El Hammammakes it possible to highlight differences in the assemblages in Foraminifera duringaverageLias. Keywords - Mounts of the ksour, AïnOuarka, Chémarikh, El Hammam, basalLias-Dogger, benthicForaminifera, Nodosariidae, associations, biodiversity, distribution paléoenvironnementale.