Quantifying Arabia–Eurasia convergence accommodated in the Greater Caucasus by paleomagnetic reconstruction

• Published in: Earth and planetary science letters 2018-01, Vol.482, p.454-469
• Main Authors: van der Boon, A., van Hinsbergen, D.J.J., Rezaeian, M., Gürer, D., Honarmand, M., Pastor-Galán, D., Krijgsman, W., Langereis, C.G.
• Format: Article
• Language: English
• Subjects: Eocene volcanics; Greater Caucasus; Iran; orocline; paleomagnetism; tectonic rotations
• ISSN: 0012-821X; 1385-013X
• DOI: 10.1016/j.epsl.2017.11.025

Since the late Eocene, convergence and subsequent collision between Arabia and Eurasia was accommodated both in the overriding Eurasian plate forming the Greater Caucasus orogen and the Iranian plateau, and by subduction and accretion of the Neotethys and Arabian margin forming the East Anatolian plateau and the Zagros. To quantify how much Arabia–Eurasia convergence was accommodated in the Greater Caucasus region, we here provide new paleomagnetic results from 97 volcanic sites (∼500 samples) in the Talysh Mountains of NW Iran, that show ∼15° net clockwise rotation relative to Eurasia since the Eocene. We apply a first-order kinematic restoration of the northward convex orocline that formed to the south of the Greater Caucasus, integrating our new data with previously published constraints on rotations of the Eastern Pontides and Lesser Caucasus. This suggests that north of the Talysh ∼120 km of convergence must have been accommodated. North of the Eastern Pontides and Lesser Caucasus this is significantly more: 200–280 km. Our reconstruction independently confirms previous Caucasus convergence estimates. Moreover, we show for the first time a sharp contrast of convergence between the Lesser Caucasus and the Talysh. This implies that the ancient Paleozoic–Mesozoic transform plate boundary, preserved between the Iranian and East-Anatolian plateaus, was likely reactivated as a right-lateral transform fault since late Eocene time. •New paleomagnetic data from the Talysh in northwest Iran from 10 localities.•Quantification of Arabia–Eurasia convergence accommodated in the Greater Caucasus.•Restoring plate kinematics of the Pontides–Talysh orocline using paleomagnetic data.•Quantification of minimum Arabia–Eurasia convergence accommodated in the Greater Caucasus.