The basement of the Variscan Axial Zone of the Pyrenees is exposed at four different levels in two elliptical gneiss dome pairs, the Bossòst and Aston-Hospitalet domes. Microstructural analyses of augengneisses of the dome core and metasedimentary rocks of the mantle reveal that the main Variscan deformation phases reflect an overall compressional tectonic regime. Strain partitioning at the roof of rigid orthogneiss or in the metasedimentary cover above ascending granitic magma resulted in discrete shear zones. Orogen-parallel extensional shear zones developed only locally to facilitate uplift of the core zones. No major extensional tectonic regime needs to be evoked.
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