-The Tithonian-Berriasian interval in the southern part of the NeuquĂ©n Basin is represented by the Vaca Muerta and the Pic un Leuf u Formations. Facies analysis and correlation of the Vaca Muerta Formation and the lower part of the Pic un Leuf u Formation in the Pic un Leuf u Anticline allow us to characterize the evolution of successive facies belts representing siliciclastic shelf and mixed ramp environments. Shoreface and offshore facies are developed on the siliciclastic shelf in the western and southern parts of the Pic un Leuf u Anticline. The offshore transition domain is characterized by storm beds and slump features, whereas the offshore domain corresponds to black to grey shales and turbidites. The mixed siliciclastic-carbonate ramp is characterized by the development of a lagoon and high-energy shoal in the proximal part of the inner ramp, whereas the distal part comprises a tidal complex. The mid-ramp zone is characterized by storm influence and the outer ramp by fine-grained deposits. Two major transgressiveregressive sequences and five high-frequency transgressive-regressive sequences are recognized. The highfrequency transgressive-regressive sequences make up three progradational sequences, an aggradationalprogradational sequence and an aggradational sequence. The geochemical characteristics and clay mineralogy of the Tithonian-Berriasian interval in the southern NeuquĂ©n Basin indicate that (1) climate played a key role in the evolution of the sedimentary environment, (2) a "normal marine" depositional environment with oxic sea water and sediment pore waters, rapidly changing to suboxic conditions at shallow depth below the seabed and (3) the occurrence of episodically restricted water-mass circulation at the onset of deposition of the Vaca Muerta Formation.Keywords: Vaca Muerta Formation / source rocks / siliciclastic shelf / mixed siliciclastic-carbonate ramp / sequence stratigraphy / oxygenation status RĂ©sumĂ© -Ăvolution palĂ©oenvironnementale de la partie sud du bassin de NeuquĂšn (Argentine) pendant l'intervalle tithonien-berriasien (formations Vaca Muerta et Pic un Leuf u) : approche multiproxy. L'intervalle tithonien-berriasien de la partie mĂ©ridionale du bassin NeuquĂ©n est reprĂ©sentĂ© par les formations de la Vaca Muerta et de Pic un Leuf u. L'analyse de faciĂšs et la corrĂ©lation de logs sĂ©dimentaires de la formation de la Vaca Muerta et de la partie infĂ©rieure de la formation de Pic un Leuf u dans l'anticlinal Pic un Leuf u a permis de mettre en Ă©vidence un environnement de rampe silicoclastique Ă©voluant vers un environnement de rampe mixte. En environnement de rampe silicoclastique, les faciĂšs de shoreface et d'offshore se localisent dans les parties ouest et sud de l'anticlinal Pic un Leuf u. La zone de transition est caractĂ©risĂ©e par des niveaux de tempĂȘte et des niveaux dĂ©structurĂ©s et slumpĂ©s, alors que le domaine d'offshore correspond Ă des marnes noires Ă grises ainsi qu'Ă des niveaux de turbidites. La rampe mixte silicoclastique-carbonatĂ©e se caractĂ©rise dans sa partie proxima...