Heterogeneidade da sucessão siliciclástico-carbonatada do topo da formação de Cabo Carvoeiro (transição Jurássico Inferior-Médio), Bacia Lusitânica, Portugal

ABSTRACT: The upper CC5 member of the Cabo Carvoeiro Formation (Toarcian-Aalenian(?)) of the Lusitanian Basin is characterized by grainstone facies with quartz grains, ooids and intraclasts. These facies are observed exclusively at Peniche, contrasting with the hemipelagic marly sediments of coeval outcrop sections in the basin. A detailed facies scheme reveals the relative local heterogeneity of the succession on outcrops, while the analysed subsurface data helps to better understand its regional heterogeneity. Lateral facies variability on outcrop is observed to occur through gradation, interfingering or pinching-out geometries. Coeval sections in the analysed offshore wells are generally characterized by micritic mudstone facies, which might transition laterally into the Peniche grainstones through similar geometric relationships based on the existing conceptual model. The relative heterogeneity of this sedimentary system is defined in this study by integrating outcrop and subsurface data, allowing for its perception at different observation scales.