Document Type : Original Research Paper


1 M.Sc., Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran

2 Associate Professor, Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran

3 Associate Professor, Department of Mining, Faculty of Engineering, University of Tehran, Tehran, Iran


Anticline axes in both orogenic belts of the Zagros and Kopeh Dagh are offset by NW-SE trending transvers faults. These faults are rotating anticlockwise due to their oblique orientation relative to maximum stress vector, causing shortening across the belt and elongation along the strike. The transverse faults move right laterally and known as prominent faults of Bajgiran, Quchan, Shokranlou, Baghan in central Kopeh Dagh; and Kazerun, Karehbas, Sabzpushan, Sarvestan in central Zagros. Faults in two regions, however, show different pattern of offset. We proposed two different physical models, consist of rotating blocks at the base overlaid by sand with and without silicon layers, resembling variation of stratigraphy in two belts. In the Zagros model, where we have more incompetent layers, offset on the basement faults causes bending of the fold axes at the surface prior to any offset. While in the Kopeh Dagh, where we have less incompetent layers, the fold axes are offset with no major change in their orientation.


Main Subjects

Bahroudi, A., and Talbot, C. J., 2003-The configuration of the basement beneath the Zagros Basin. Journal of petroleum geology26(3), 257-282,
Blanc, E. P., Allen, M. B., Inger, S., and Hassani, H., 2003-Structural styles in the Zagros simple folded zone, Iran. Journal of the Geological Society160(3), 401-412,
Hollingsworth, J., 2008- Active tectonics of NE Iran (Doctoral dissertation, University of Cambridge), 239P.
Hollingsworth, J., Jackson, J., Walker, R., Gheitanchi, M. R., and Bolourchi, M. J., 2006- Strike-slip faulting, rotation, and along-strike elongation in the KopehDaghmountains, NE Iran. Geophysical Journal International166(3), 1161-1177,
Jackson, J., and Molnar, P., 1990- Active faulting and block rotations in the western Transverse Ranges, California. Journal of Geophysical Research: Solid Earth95(B13), 22073-22087,
Krantz, R.W., 1991- Measurements of friction coefficients and cohesion forfaulting and fault reactivation in laboratory models using sand and sandmixtures.Tectonophysics, 188, 203–207,
Lamb, S. H., 1987- A model for tectonic rotations about a vertical axis.Earth and Planet.Sci. Lett., v. 84, pp.75-86,
Lyberis, N., Manby, G., Poli, J.T., Kalougin, V., Yousouphocaev, H. and Ashirov, T., 1998- Post-Triassic evolution of the southern margin of the Turan plate. ComptesRendus de l'Académie des Sciences-Series IIA-Earth and Planetary Science, 326(2), pp.137-143.
Shabanian, E., 2009- Active tectonic study in northeast Iran: contribution of the KopehDagh and Binalud mountains to the accommodation of the Arabia-Eurasia convergence (Doctoral dissertation, Université Paul Cézanne-Aix-Marseille III).
Robert, A. M., Letouzey, J., Kavoosi, M. A., Sherkati, S., Müller, C., Vergés, J., and Aghababaei, A., 2014- Structural evolution of the KopehDagh fold-and-thrust belt (NE Iran) and interactions with the South Caspian Sea Basin and Amu Darya Basin. Marine and Petroleum Geology57, 68-87,
Ruttner, A.W., Brandner, R. and Kirchner, E., 1991- Geology of the Aghdarband area (kopetDagh, NE-Iran). Abhandlungen der GeologischenBundesanstalt, 38, pp.7-79.
Talebian, M., and  Jackson, J., 2004-A reappraisal of earthquake focal mechanisms and active shortening in the Zagros mountains of Iran. Geophysical Journal International, 156(3), 506-526,
Tchalenko, J. S., 1975- Seismicity and structure of the KopetDagh (Iran, USSR).Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 278(1275), 1-28,
Vernant, P., Nilforoushan, F., Hatzfeld, D., Abbassi, M. R., Vigny, C., Masson, F., Nankali, H., Martinod, J., Ashtiani, A., Bayer, R., Tavakoli, F., and Chéry, J., 2004- Present-day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman.Geophys.. J. Int.157, 381-398,
Walpersdorf, A., Hatzfeld, D., Nankali, H. ,Tavakoli, F., Nilforoushan, F., Tatar, M., Vernant, P., Chery, J., Masson, F., 2006- Difference in the GPS deformation pattern of North and Central Zagros (Iran).Geophys. J. Int. 167, 1077-1088,
Zanchi, A., Zanchetta, S., Balini, M., Ghassemi, M. R., 2016- Oblique convergence during the Cimmerian collision: evidence from the Triassic Aghdarband Basin, NE Iran. Gondwana Research, 38, 149-170,