Palaeomagnetism of Permian and Triassic red beds of NW Spain and implications for the tectonic evolution of the Asturian—Cantabrian Arc

A palaeomagnetic study of Permo-Triassic cover rocks in the Asturian—Cantabrian Arc has revealed characteristic magnetizations in 136 samples from 14 sites, yielding a mean palaeopole for each of the three regions studied (Cabo de Peñas, Villaviciosa, and Tudanca). Previous work on remagnetized Palaeozoic formations in the area revealed Permian (or younger) tightening of the Arc on the basis of palaeomagnetic declinations that show relative rotations of more than 100°. According to the new palaeopoles obtained in this study, these rotations are not present to any comparable extent in the Permo-Triassic deposits, allowing us to conclude that the bulk of the rotations in the Arc is Permian in age.