Extending the Cantabrian Orocline to two continents (from Gondwana to Laurussia). Paleomagnetism from South Ireland

• Published in: Earth and planetary science letters 2015-12, Vol.432, p.223-231
• Main Authors: Pastor-Galán, Daniel, Ursem, Bart, Meere, Patrick A., Langereis, Cor
• Format: Article
• Language: English
• Subjects: Boundaries; Compatibility; Continents; Earth; Expansion; Oceans; Orocline; paleomagnetism; Pangea; Rocks; Shear zone; tectonics; Variscan; vertical axis rotation
• ISSN: 0012-821X; 1385-013X
• DOI: 10.1016/j.epsl.2015.10.019

Regional Variscan structure in southern Ireland follows a gentle arcuate trend of ca. 25° concave to the SE that apparently follows the geometry of the Cantabrian Orocline (NW Iberia) when Iberia is restored to its position prior to the opening of the Biscay Bay. We report paleomagnetic results from Devonian and Carboniferous rocks in southern Ireland: (i) a pervasive and consistent remagnetization during the Late Carboniferous and (ii) an average rotation of ∼25° counterclockwise with respect to the Global Apparent Polar Wander Path and kinematically compatible with the Cantabrian Orocline. These results support the participation of Laurussia in the formation of the Cantabrian Orocline involving, at least, southern Ireland and the South Portuguese Zone (S Iberia). We conclude that a Greater Cantabrian Orocline extends beyond its current boundaries to include shear zones in the Variscan hinterland and the Rheic Ocean suture, thereby enlarging its size to plate-scale affecting as it does the Laurussia and Gondwana margins. •South Ireland rotated 25° clockwise during the Late Carboniferous.•The 25° CW rotation fits kinematically with the Cantabrian Orocline.•Altogether form the Greater Cantabrian Orocline.•Gondwana and Laurussia are involved into a plate-scale orocline.