serie NOVA TERRA nº 49

53 2. Geological setting of the arc-derived terrane The upper units of the allochthonous complexes of NW Iberia represent a well-preserved section of a peri-Gondwanan magmatic arc. These units are well exposed in the Cabo Ortegal and Órdenes complexes, and include a large variety of lithologies ( Fig. 3 ). The internal structure of the upper units is characterized by the presence of two sheets that display slightly different tectonothermal histories. The lower sheet (HP – HT upper units) is a polymetamorphic assem- blage affected by a widespread high-pressure and high-temperature metamorphic event, the age of which is estimated to be 410 – 390 Ma ( Ordoñez Casado et al., 2001; Fernández Suárez et al., 2007 ). This Fig. 2. Geological map of NW Iberia. It shows the distribution of the Autochthon and Parautochthon domains and the main terranes involved in the allochthonous complexes located in the most internal part of the belt. 340 J.M. Fuenlabrada et al. / Gondwana Research 17 (2010) 338 – 351