Reappraisal of the palaeomagnetism of the Miocene intramontane Pag and Drniš–Sinj basins, External Dinarides (Croatia)

Abstract

This paper presents paleomagnetic results from the Miocene offshore Pag and the twin onshore (Drniš-Sinj) basins. Earlier magnetostratigrapic results were published from both basins, which documented that the lake sediments were good targets for paleomagnetism.From the Pag basin, we sampled the oldest and youngest segments of the 1200m long Crnika section and obtained statistically different paleomagnetic directions from the two parts.During a repeated visit to the section it was revealed that modern gravity-driven creeping can account for this, i.e. the results from the Pag basin should be rejected from regional tectonic interpretation.The overall-mean paleomagnetic direction for the Drniš-Sinj basin has excellent statistical parameters, its high quality is further supported by positive regional fold/tilt and reversal tests, based on seven geographically distributed localities. The results suggests 13-20° CCW rotation with respect to Africa and 21-27° with respect to stable Europe, during the last 15 million years. As the External Dinarides are the loci of a complicated network of Miocene and even younger tectonic zones, we can not export the observed rotation for the whole unit, but consider our results as one step in obtaining robust kinematic constraints for the post-Oligocene tectonic history of the External Dinarides.