Sédimentologie et Ostracodes de la Limite Eifelien-Givetien à Resteigne (Bord Sud Du Bassin de Dinant, Belgique)

The global cyclic succession of the microfacies from the Upper Eifelian to Lower Givetian times shows evidence of shallowing from deeper settings, unaffected by storm-reworking, into «proximal» above storm wave base settings, near a shoreline coast. This overall regressive progradational megasequence indicates that deposition could have occurred on a ramp setting without any kind of continuous rims and-or typical lagoonal facies behind them. This general upward-coarsening progradational evolution corresponds probably to a phase of reduced sea-level rise or stillstand on the top of which the ramp setting has evolved into a carbonate progradational accretionnary platform. Forty-one ostracod species are reported and twenty-four described from the Hanonet Formation and from the base of the Trois-Fontaines Formation of the Resteigne quarry. Sixteen are known mainly from Germany and Poland and five of them are closely related to well established species. Sixteen species are placed in open nomenclature, three of which are new, and eight are comparable with previously described data. Aparchites resteignensis n.sp. is described in detail. The ostracod fauna indicates a shallow marine environment and an increase of water agitation near the Eifelian/Givetian boundary