Evidence of widespread Cretaceous remagnetisation in the Iberian Range and its relation with the rotation of Iberia

Abstract

A palaeomagnetic investigation has been carried out at 13 sites of Jurassic age in the Iberian Range (northern Spain). Two components of remanent magnetisation have been found at each site. A primary high-temperature component shows an average counterclockwise rotation with respect to the north of 33±2° clockwise about a vertical axis corresponding to the absolute rotation of the Iberian plate since the Jurassic. A secondary low-temperature component shows a systematic declination difference of 16±4° with respect to the primary component. This indicates that a rotation of Iberia must have occurred between the two acquisition times. Comparison of the magnetisation directions with previous palaeomagnetic data and with sea-floor spreading data, constrains the age of the remagnetisation between 95 and 125 Ma. The remagnetisation may be associated with the extensional phases in the Iberian Basin in the Early Cretaceous (Barremian–early Albian) or Late Cretaceous (Cenomanian). A principal characteristic of the remagnetisation is its widespread character in the Iberian Range.