GENESIS OF THE IBERO-ARMORICAN ARC

The Ibero-Armorican are is continuous between Iberia and Armorica; its curvature increased with time due to subduction followed by continent al collision; indentation produced left lateral transpression in Iberi a and right-lateral transpression in Armorica. It is argued that where as the antithetic shear is predominant in Iberia, in Armorica a synthe tic shear prevailed because the identer rotated anticlockwise between the opposed forelands of the Variscan Fold Belt. It is proposed that t he major Rheic ocean, closed by subduction towards the inner part of t he are, solving the space problem of centripetal vergences.