The onset of the assembly of Pangaea in NW Iberia: Constraints on the kinematics of continental subduction

Abstract

Excellent exposures of high-pressure rocks developed in a Variscan continental subduction system outcrop in NW Iberia. The kinematic criteria provided by the high-pressure metamorphic fabrics can be used to infer tectonic flow within the deep sections of this system. The dominant trend of the ductile flow is oblique to that of the orogenic belt, indicating oblique continental subduction. Its azimuth, a few tens of degrees clockwise relative to the orogenic trend, suggests dextral transpression between Gondwana and Laurussia during continental subduction that took place at the Upper Devonian, and provides a consistent kinematic reference for the earliest assembly of Pangaea in NW Iberia.