Central and Southern Adriatic islands: tectonic implications of new paleomagnetic results

The Central and Southern Adriatic islands, situated offshore of the Split-Dubrovnik segment of the mainland, belong to the External Dinarides. Their dominant tectonic trend is W-E, significantly different from the general Dinaric NW-SE orientation. For this reason, they are often regarded as belonging to a distinct tectonic unit, and sometimes a vertical axis counterclockwise (CCW) rotation is invoked to explain the deviation from the general tectonic trend.

In this paper, new paleomagnetic results are presented from Late Jurassic through Paleocene shallow water limestones from the Central and Southern Adriatic islands. For the localities sampled for paleomagnetic investigation, the sedimentological properties and the stratigraphic ages, based on the foraminifera population, were checked by microscopy investigation. The paleomagnetic analysis was carried out on field oriented drill cores, according to standard laboratory processing. The results were evaluated statistically on locality level. Overall-mean paleomagnetic directions were computed for several age groups and the age of the acquisition of the remanence was estimated from between-locality fold tests for a number of age groups. Comparison with earlier published results from the Northern Adriatic islands and from Stable Adria lead to the conclusion that the Central and Southern Adriatic islands had not rotate with respect to the Northern ones and even more importantly, stable Adria and the offshore External Dinarides must have moved as an integrated unit, at least from the Albian on.

This work was financially supported by the National Development and Innovation Office of Hungary project K 128625.