Distribución de facies en un sistema volcánico submarinoFormación Errigoiti, Albiense-Santoniense (Bizkaia, Cuenca Vascocantábrica)

Resumen

The Errigoiti Fm. is an Albian to Santonian bathyal submarine volcanic system of alkali basaltic character. These volcantes were developed on thin continental crust during extensional tectonics linked to the spreading of the nearby Bay of Biscay. The volcanic products were mainly of effusive character and were grouped in four facies: sheet lavas, pillow lavas, pillow breccias and stratified volcaniclastites. Analysis of lateral and vertical facies evolution enabled us to propose a depositional model consisting of three volcanic environments, these are: amalgamated pillow volcanoes, scattered pillow volcanoes and volcanic fringe, which reflect a proximal-to-distal evolution from a pillow lavas/pillow breccias/stratified volcaniclastites facies association to a sheet lavas/pillow lavas/stratified volcaniclastites facies association and, finally, to a sheet lavas/stratified volcaniclastites facies association. The facies distribution of the Errigoiti Fm. is a stratigraphic model than can improve the study of the most common of the volcanism, the submarine basic volcanic system, whose analysis from a stratigraphic-sedimentological point of view is still poorly developed.