New geochronological data on the Late Cretaceous alkaline magmatism of the northeast Iberian Peninsula

Alkaline magmatic activity took place in the Iberian Peninsula during the Late Cretaceous, between c. 100 and c. 65 Ma. This magmatism is well known only in southern Portugal and the Pyrenees. We present 40Ar/39Ar and K/Ar ages from three alkaline lamprophyres (camptonites) located in the Catalan Coastal Ranges. The ages obtained (80, 76 and 69 Ma) indicate that the intrusives concerned represent the youngest Mesozoic alkaline magmatism dated so far in the northeast Iberian Peninsula, establishing a link between the Pyrenean and Portuguese alkaline magmatism. Their position at the margin of the Iberian Plate is noteworthy and indicates the presence of zones of cortical relaxation (and perhaps thinning) after Iberian Plate rotation and during ocean-floor spreading in the North Atlantic.