EVIDENCE OF WIDESPREAD CRETACEOUS REMAGNETISATION IN THE IBERIAN RANGE AND ITS RELATION WITH THE ROTATION OF IBERIA

A palaeomagnetic investigation has been carried out at 13 sites of Jur assic age in the Iberian Range (northern Spain). Two components of rem anent magnetisation have been found at each site. A primary high-tempe rature component shows an average counterclockwise rotation with respe ct to the north of 33 +/- 2 degrees clockwise about a vertical axis co rresponding to the absolute rotation of the Iberian plate since the Ju rassic. A secondary low-temperature component shows a systematic decli nation difference of 16 +/- 4 degrees with respect to the primary comp onent. This indicates that a rotation of Iberia must have occurred bet ween the two acquisition times. Comparison of the magnetisation direct ions with previous palaeomagnetic data and with sea-floor spreading da ta, constrains the age of the remagnetisation between 95 and 125 Ma. T he remagnetisation may be associated with the extensional phases in th e Iberian Basin in the Early Cretaceous (Barremian-early Albian) or La te Cretaceous (Cenomanian). A principal characteristic of the remagnet isation is its widespread character in the Iberian Range, (C) 1998 Els evier Science B.V. All rights reserved.