Distribución estratigráfica de los episodios volcánicos submarinos del Albiense-Santoniense en la Cuenca Vasca (sector Gernika-Plentzia, Bizkaia)

Abstract

In the central domain of the Basque-Cantabrian Basin (Gernika-Plentzia sector) it has been characterized seven volcanic episodes, framed in the cretaceous alkali basaltic eruptive period. These comprise sheet lavas, pillow lavas, pillow breccias, primary stratified volcaniclastites, recycled volcaniclastites and volcaniclasts involved in purely epidastic deposits. These volcanic episodes are framed in deep sea calciclastic/ terrigenous turbidite systems and hemipelagic sediments ranging from upper Albian (episode 7 to 4), lower Cenomanian (episode 5), lowermost Turonián (episode 6) and uppermost Coniacian-lower Santonian (episode 7).

Their stratigraphic arrangement within the sequence stratigraphic framework, characterized in the turbidite/ pelagic units, suggest that these volcanic episodes reach their climax at the base of the depositional sequences. The volcanic episodes are widespread developed on submarine paleohighs related to deep-seated faults trending N30/60 and N7 20/7 50 which bound basin block with high rates of differential subsidence. These evidences reinforce the hypothesis that both, the genesis of these volcanic episodes and sequence boundary development, are related to the same tectonic event