engleski

Inconsistent tectonic trends, consistent paleomagnetic directions: an example from External Dinarides

The Central Dalmatian islands between Split and Dubrovnik are of special interest, since their orientations and structural trends are WNW-ESE, instead of the general NW-SE Dinaric trend. For this reason we made an extensive paleomagnetic study on more than 600 oriented cores from 43 localities. The samples represent shallow-water platform carbonates of Lower Cretaceous through Campanian in age from Mljet, Korčula and Hvar islands and also Upper Jurassic age from Mljet island. Hand samples were taken for biostratigraphic determination from the sampled beds in the outcrops. Based on the stratigraphic ages a Campanian – Santonian (only Hvar island), a Cenomanian – Turonian (all islands), an Aptian – Albian plus a Tithonian – Barremian (Mljet and Korčula islands) paleomagnetic overall mean directions could be defined. For the first two groups positive tilt test constrained the age of the magnetizations as of pretilting age, for the last two the tilt test is indeterminate. Earlier published coeval paleomagnetic directions from the Northern Adriatic islands and Vis (Márton et al., 2014) suggest exactly the same magnitude of CCW rotation as the islands of the present study, at least from the Cenomanian on. Thus, the above mentioned difference in tectonic trends can not be attributed to differential mass rotations, but considered e.g. as the consequence of deformations at different times (Korbar, 2009).

Jurassic, Cretaceous, Central Dalmatian Islands, paleomagnetic direction, CCW rotation

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