Caracterización Paleoambiental del miembro inferior de la formación Quintuco en el Yacimiento estación Fernández Oro a partir de la integración de datos de corona.

Abstract

The Quintuco Formation was deposited during the late Berriasian to early Valanginian and comprises sequences of claystones, calcareous sandstones, limestones, dolomites, and anhydrites, which overlie the Vaca Muerta Formation and underlie the Centenario Formation in the Catriel platform and Bajo de Añelo. This formation, together with it’s proximal platform equivalent, the Loma Montosa Formation, constitutes one of the most diversified and widely distributed carbonate reservoirs in the entire Neuquén Basin. Within the Estación Fernández Oro deposit, located on the morphostructural domain of the Huincul High, the Quintuco Formation consists of a lower sandy member, traditionally interpreted as a wave-dominated shoreface environment influenced by nearby fluvial systems, and an upper calcareous member, which comprises oolitic-bioclastic platform deposits. In this study, 27 m of core samples from well Pi.RN.EFO-76 were analyzed. These cores mainly consist of sandstone facies, with minor occurrences of fine conglomerates and mudstones, generally displaying a coarsening-upward stacking pattern. Additionally, towards the top of the succession, marked signs of stress in the benthic fauna were observed, primarily associated with fluctuations in salinity levels and variations in sedimentation rates. All this evidence allows reinterpreting the unit in this position in the basin, assigning an origin linked with the downdrift progradation of a deltaic system, strongly influenced by fair-weather wave action and storm events, occasionally developing density flows triggered by the destabilization of mouth bars in the delta front.