U-Pb zircon age of Ordovician magmatism in the Albera Massif (Eastern Pyrenees)

Abstract

New geochronological data from the Albera Massif confirm the presence of an Early – Mid Ordovician igneous
event (472 - 465Ma) recorded in the pre-Variscan rocks of the Pyrenees. This event resulted in the emplacement
of a large granitic body in the lower part of the pre-Upper Ordovician metasedimentary succession and in the
intrusion of a series of metric sized dykes in the middle and upper parts of it. The two types of igneous rocks
were gneissified during subsequent Variscan deformation. The geochronological data confirm the occurrence of
the gneiss as having derived from an Ordovician intrusive sheet, as in other Pyrenean massifs. The dykes are
considered to be the subvolcanic equivalent of the intrusive sheet. The data also provide insight into the age of the
metasedimentary series of the massif and enable us to correlate the dated rocks with other gneissic and subvolcanic
bodies of the Variscan massifs of the Pyrenees and Iberia.