Análisis paleoambiental de la Formación Mata Amarilla a partir de su malacofauna, Cuenca Austral, Patagonia, Argentina.

VARELA, AUGUSTO; RICHIANO, SEBASTIÁN; POIRE, DANIEL G.

Mar del Plata

Congreso; VII Congreso de Exploración y Desarrollo de Hidrocarburos; 2008

IAPG Instituto Argentino del Petróleo y del Gas

Paleoenvironmental analysis of the Mata Amarilla Fm using its malacofauna, Austral Basin, Patagonia Argentina. We present here a paleoenvironmental model for the Lower Upper Cretaceous lower section of the Mata Amarilla Fm., in the Austral Basin. This work is made from detailed sedimentologic logs, facies analysis, and the study of its paleontological content and taphonomics attributes. The unit is composed of alternating white sands and mudstones, with bioclastic accumulations interbedded in the lower section. The depositional environment for the Mata Amarilla Fm. is a lagoon limited by shallow marine bars. The fine sedimentation is sporadically interrupted by storm events represented by coquines, bioclastic sands and shell pavements with an heterogeneous and allochtonous malacofauna association. Some areas of the lagoon become exposed allowing the development of vegetation on the susbstrate and the generation of pedogenetic processes. Subsequently, an advanced regression stage occurs when a fluvial system invades the lagoon area representing the beggining of the Mata Amarilla Fm. upper section deposition.