Abstract

In Celtiberia (middle of NE Spain), some small, scattered areas preserve Devonian of the depocentre of the Westasturian-Leonese Zone that belongs to the Ibero-Armorican Trough. 4,000 m of siliciclastics with many thin calcareous horizons (conodont zoned) are known up to middle Famennian. Marked rhythmicity controls the vertical distribution of orthoquartzites, phosphate lags, iron oolites, intertidal facies, pelagic black shales, and limestones, and causes many vertical changes between Rhenish, Bohemian and Hercynic biofacies. This makes Celtiberia a key area for worldwide correlation. By comparison with Armorica, inter-regional transgressive tendencies can be separated from local effects. Rhenish stages of the Early Devonian are calibrated here by means of lineages of rapidly evolving brachiopods, trilobites and conodonts in Rhenish facies and are correlated by means of pelagic conodonts, dacryoconarids and goniatites. The stratigraphy is described with reference to the paleogeography and structural history of SW Europe and NW Africa. The Ibero-Armorican Trough leads from central Brittany around the Cantabrian Knee to Celtiberia (1,300 km) and is possibly continued around the slightly emergent Centroiberia, which was a longitudinally growing structure due to a mantle plume. The Cantabro-Ebroian Massif (northeast of the trough) was not always the main source area. Benthos of Ibero-Armorica and NW Africa define a Mauro-Ibero-Armorican faunal province, especially in the Early Devonian; endemic taxa coexist with Rhenish and Bohemian ones. This sets strict limits to plate tectonics.