International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

Paleomagnetic detection of Tertiary rotations in the Southern Pannonian Basin (Fruska Gora)

Pages: 185 - 193

Authors: VESNA LESIC, EMO MARTON, VESNA CVETKOV

Abstract: Fruska Gora is an inselberg in the Southern Pannonian Basin. It is partially covered and surrounded by Miocene sediments, which were the main targets of our paleomagnetic study. The aim was to see if Fruska Gora participated in the young counterclockwise rotation observed at several points in the western part of the Southern Pannonian Basin. Nevertheless, we also sampled Oligocene latites and a few Mesozoic localities. From 16 localities 14 yielded results. Geographically distributed Miocene and pre-Miocene localities with a Miocene overprint (overall-mean paleomagnetic direction: D=320º, I=54º, k=26, α95=12º) indicate that the Fruska Gora rotated in co-ordination with the western Southern Pannonian Basin close to the end of the Miocene (Early Pliocene). This rotation must have been driven by the Adriatic microplate. The overall-mean paleomagnetic direction for Oligocene latite and contact metamorphosed Upper Cretaceous flysch is D=220º, I=–43º, k=25, α95=16º (corrected for the general tilt of the Miocene sediments), suggesting about 40º clockwise rotation with respect to the present North. This means a total clockwise rotation of about 80º, occurring before the mid-Miocene and after the intrusion of the latite, possibly confined to one of the blocks of the Fruska Gora horst. It is equally possible that the clockwise rotation affected a larger area. In any case, both the clockwise and the counterclockwise rotations are important for the kinematic reconstruction of the Fruska Gora with respect to the Vardar Zone, to which it belonged originally. Future work should provide paleomagnetic data from the Vardar Zone in order to facilitate this reconstruction.

Keywords: Tertiary rotations, Southern Pannonian Basin, Fruska Gora, paleomagnetism

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