TY  - JOUR
A1  - Ballato, Paolo
A1  - Stockli, Daniel F.
A1  - Ghassemi, Mohammad R.
A1  - Landgraf, Angela
A1  - Strecker, Manfred
A1  - Hassanzadeh, Jamshid
A1  - Friedrich, Anke M.
A1  - Tabatabaei, Saeid H.
T1  - Accommodation of transpressional strain in the Arabia-Eurasia collision zone new constraints from (U-Th)/He thermochronology in the Alborz mountains, north Iran
JF  - Tectonics
N2  - The Alborz range of N Iran provides key information on the spatiotemporal evolution and characteristics of the Arabia-Eurasia continental collision zone. The southwestern Alborz range constitutes a transpressional duplex, which accommodates oblique shortening between Central Iran and the South Caspian Basin. The duplex comprises NW-striking frontal ramps that are kinematically linked to inherited E-W-striking, right-stepping lateral to obliquely oriented ramps. New zircon and apatite (U-Th)/He data provide a high-resolution framework to unravel the evolution of collisional tectonics in this region. Our data record two pulses of fast cooling associated with SW-directed thrusting across the frontal ramps at similar to 18-14 and 9.5-7.5 Ma, resulting in the tectonic repetition of a fossil zircon partial retention zone and a cooling pattern with a half U-shaped geometry. Uniform cooling ages of similar to 7-6 Ma along the southernmost E-W striking oblique ramp and across its associated NW-striking frontal ramps suggests that the ramp was reactivated as a master throughgoing, N-dipping thrust. We interpret this major change in fault kinematics and deformation style to be related to a change in the shortening direction from NE to N/NNE. The reduction in the obliquity of thrusting may indicate the termination of strike-slip faulting (and possibly thrusting) across the Iranian Plateau, which could have been triggered by an increase in elevation. Furthermore, we suggest that similar to 7-6-m.y.-old S-directed thrusting predated inception of the westward motion of the South Caspian Basin. Citation: Ballato, P., D. F. Stockli, M. R. Ghassemi, A. Landgraf, M. R. Strecker, J. Hassanzadeh, A. Friedrich, and S. H. Tabatabaei (2012), Accommodation of transpressional strain in the Arabia-Eurasia collision zone: new constraints from (U-Th)/He thermochronology in the Alborz mountains.
Y1  - 2013
U6  - https://doi.org/10.1029/2012TC003159
SN  - 0278-7407
VL  - 32
IS  - 1
SP  - 1
EP  - 18
PB  - American Geophysical Union
CY  - Washington
ER  -