OSTRACODS AND SEDIMENTOLOGY FROM THE EIFELIAN-GIVETIAN TRANSITION IN THE MARBLE QUARRY OF PIC-DE-VISSOU (MONTAGNE-NOIRE, FRANCE)

Forty-three species, the majority of which are figured, have been reco rded in the late Eifelian and the Givetian of the Pic de Vissou quarry . Six new species are introduced: Samarella porrecta nov, sp., Cythere llina musculosa nov. sp,, Healdianella? dorsostriata nov. so., Ampuloi des mourezensis nov, sp., Ampuioides vissouensis nov. sp. and Bairdioc ypris postsoetenica nov. so. The ostracod assemblage belongs to the Ei felian ecotype and is indicative of a well oxygenated and moderately d eep water environment below the level oi wave action, and generally be low storm wave base. Sedimentological analysis allows recognition of s ix major microfacies families ranging from open marine environments, b elow or close to the storm wave action, to relatively shallow environm ents near the fair weather wave base. The deepest environments are dom inated by hemipelagic communities rich in Styliolina while the shallow ones show echinoid and bryozoan communities reworked from a destabili zed shelf. Sequential analysis does not allow direct bathymetric compa risons. It shows however that the transitional Eifelian-Givetian layer s recorded a clearly transgressive event following a three-step evolut ion.