engleski

New stepping stones in the systematic paleomagnetic study of the Adriatic-Dinaric carbonate platform: Dugi otok and Vis islands

During recent years, a systematic paleomagnetic study was carried out on Jurassic-Eocene rocks from stable Adria, from the northern Adriatic islands and coastal range. Although pioneer investigations touched some of the mentioned areas and a considerable part of the paleomagetic directions obtained in the 1970-80s are acceptable today the areal cover is obviously not. Progress in carbonate sedimentology, biostratigrapy and in paleomagnetic evaluation techniques promised a larger number of good paleomegnetic directions, especially from the extremely weak magnetic platform carbonates, which are the subjects of the present study from two Adriatic islands, Dugi otok and Vis. Some place the two islands to the same, others to different tectonic units and we intended to test the different models. On Dugi otok and Vis islands we drilled Cretaceous platform carbonates at a total of 48 localities for paleomagnetism and collected hand samples for biostratigraphic checking of the age. As a result of standard laboratory processing, 30 localities yielded good paleomagnetic results and three overall mean paleomagnetic directions were defined for each island. The two Early Cretaceous directions are different, while the Albian-Cenomanian ad the Turonian-Santonian ones are coinciding. Thus, relative movement between the islands can not be excluded before the mid Albian, while the islands must have moved in co-ordination afterwards. The paleomagnetic results from Vis and Dugi otok are in perfect agreement with paleomagetic directions from stable Adria, from the northern Adriatic islands (Cres, Ist and surroundings) implying that all these areas moved in co-ordination, at least from the Late Albiaan on.The coastal range of the External Dinarides exhibits about 300 CW rotation with respect to them, which is in contra direction for placing any of the so far studied Adriatic islands into the High Karst unit.

Stable Adria; Imbricated Adria; External Dinarides; Mesozoic

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