Variscan accretionary complex of northwest Iberia: Terrane correlation and succession of tectonothermal events

Abstract

The allochthonous terranes of northwest Iberia can be correlated with specific paleogeographic
realms of the continental masses and intervening oceans involved in the Variscan collision.
Assuming that the existing ophiolites represent the suture formed by the closure of the
Rheic ocean, the units in the footwall to the suture correspond to the outer edge of the Gondwana
continental margin, and the units in the hanging wall are interpreted as fragments of the
conjugate margin, represented by the Meguma terrane. This correlation establishes a precise
link between circum-Atlantic terranes, and makes it possible to draw a relatively simple scenario
of the successive tectonothermal events recorded. Following the amalgamation of Avalon
to Laurentia, the remaining outboard terranes underwent a progressive accretion to this continent
that ended with the collision between Laurentia and Gondwana.