Dextral rotations and tectonomagmatic evolution of the southern Rhodope and adjacent regions (Greece)

Palaeomagnetic measurements deduced from Eocene, Oligocene, Miocene and Pli ocene formations, exposed in the Greek Rhodope and surrounding areas, revea l significant clockwise rotations, displaying an apparent systematic increa se in magnitude from Thrace westwards and a decrease northwards. The Pelago nian zone in the west has suffered no rotation, at least since the Late Mio cene. A transition from rotated to unrotated regions seems to exist close t o the western boundary of the Vardar zone. No rotations are apparent earlie r than the mid-Oligocene. Parts of the Rhodope may have been rotated clockw ise by similar to 12 degrees during the Late Oligocene. Additional clockwis e rotations occurred after the Early Miocene. It is proposed that at least the post Early Miocene rotations were the result of plate tectonic motions in the north Aegean area, initiated by Middle Miocene times and continuing to the present day. Southward stretching and bending of the ductile part of the lithosphere was accomplished at brittle upper-crustal levels by the de tachment, translation and rotation of the upper plate of the Rhodope core c omplex (the Serbomacedonian element), possibly followed by further fragment ation and rotation of individual blocks. (C) 1998 Elsevier Science B.V. All rights reserved.