Mixed clastic-carbonate sedimentation of the Yacoraite Formation (Maastrichtian-Danian), Salta Group, NW Argentina

GALLI, C.I.; VILLALBA ULBERICH, J.P.; SCHMIDT, W.; MUTTI, M.

Selva di Val Gardena

Congreso; Dolomieu Conference on Carbonate Platforms and Dolomite.; 2016

American Association of Petroleum Geologist

Concepts of reciprocal sedimentation predict vertical alteration of classics and carbonates and their lateral continuity in the basin. In shallow-marine mixed siliciclastic-carbonate environments, significant lateral and vertical facies heterogeneity is to be expected. Outcrop studies, facies analysis and the correlation of stratigraphic sections enable the understanding of facies spatial distribution and change. The Tres Cruces subbasin as the northern extent of the triradiate Salta basin (NW Argentina) is an important connector between the latter and the Potosi basin (Bolivia) within the Eastern Cordillera. The sub basin allows the the possibility of integration of subbasin-scale depositional geometry with detailed facies description, using petrographic and petrophysical investigations and diagenetic studies with focus on specific facies and relevant marker surfaces. Focus of this work is the Yacoraite Formation, an Upper Cretaceous to Palaeocene post-rift sedimentary succession of bioclastic, oolitic and stromatolitic limestones alternating with green to purple marls. It is part of the Salta Group, which comprises Lower Cretaceous to Eocene synrift and postrift deposits of the Salta rift and extends lateral continuous throughout the Salta basin. The aim of this project is first to improve the understanding of the depositional history of the Yacoraite Formation in the aforementioned region. Six stratigraphic sections have been measured and their correlation should allow the characterisation of geometries and facies of the Yacoraite Formation throughout the Tres Cruces subbasin. Such allow the investigation of marine ingression and terrestrial influx pattern, but also control factors on the reciprocal sedimentation.