engleski

Reference apparent polar wander curve for Adria from direct measurement on late Jurassic-Cretaceous sediments in autochthonous position

Adria, the largest lithospheric fragment in the Central Mediterraneum, s the foreland of the Apennines, the Southen Alps and the Dinarides. The kinematic reconstruction of the mentioned mobile belts requires that we have a full control on the kinematics of the foreland. Direct paleomagnetic data from stable Adria were, however, not the best quality and also somewhat controversal. This explains why attempts were made to transfer paleomagnetic poles from related mobile areas to stable Adria, a procedure not without risk. In this paper we are presenting new paleomagnetic results from two parts of stable Adria, the Adige embayment, in Northern Italy and from stable Istria, in Croatia. These two areas represent Mesozoic, in outcrops mostly Cretaceous basin and platform facies, respectively. In both areas, a large number of geographically distributed localities were sampled and the sample subjected to standard paleomagnetic procedure. The results suggest that the two areas were displaced with respect to each other. Therefore, the coeval paleomagnetic directions from both can be used in combination. In both data set now available, Cenomanian and younger Cretaceous is the best represented, followed by Albian. The Tithonian-Aptian segment is quite poor, for lack of evidence for the age of the obtained paleomagnetic directions. Nevertheless, it is interesting that the length of the Cretaceous segment of the new apparent polar curve for Adria is quite short and corresponds to the coeval segment of the synthetic African polar wander curve (Besse & Courtillot, 2002, 2003). The former is slightly displaced relative to the latter, but the counter-clockwise rotation suggested by the displacement is less that the one observed for the Eocene (Marton et al., 2003).

Adria; Stable Istria; Adige embayment; Jurassic; Cretaceous; apparent polar wander

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