Palaeomagnetism as a tool for testing geodynamic models in the North Aegean: convergences, controversies and a further hypothesis

Abstract

Abstract The north Aegean region is a geologically complicated area, in which numerous studies have focused during the last decade. Palaeomagnetism can give a decisive contribution in selecting possible models. In the present study all available palaeomagnetic data from the north Aegean and surrounding area (39.5°N to 42°N and 20°E to 26°E) are compiled, classified and evaluated. Their significance in terms of the rotational behaviour is given as follows. In various plutonic, volcanic (Eocene-Oligocene) and sedimentary (Mio-Pliocene) formations, systematic easterly declinations are observed. The rare exceptions are caused either by remagnetized material or by very local phenomena. The declination gradually increases from recent to older periods, varying between approximately 20° and 40°. This distribution is seen in the area between south Albania and the western Greek Rhodope. In contrast, the eastern Greek Rhodope appears to be unrotated. The inclinations diverge systematically from the expected values. This could be due to either an alternative pole position for the Eocene (Westphal 1993) or possible tilting of blocks during the Oligocene-Miocene, associated with a NE-SW brittle-ductile extensional stress field. The data partially confirm geodynamic models proposed for the area by Taymaz et al. (1991), Sokoutis et al. (1993) and Jolivet (1993). The model proposed by Dinter & Royden (1992) does not predict rotations and is not supported by the palaeomagnetic data. When the published volcanological, structural, seismic and palaeomagnetic data are combined they suggest that the north Aegean region during the Early Tertiary was tectonically similar to the present day active south Aegean subduction zone.