Right-lateral shear across Iran and kinematic change in the Arabia-Eurasia collision zone

Abstract

S U M M A R YNew offset determinations for right-lateral strike-slip faults in Iran revise the kinematics of the Arabia-Eurasia collision, by indicating along-strike lengthening of the collision zone before a change to the present kinematic regime at ∼5 Ma. A series of right-lateral strike-slip faults is present across the Turkish-Iranian plateau between 48 • E and 57 • E. Fault strikes vary between NW-SE and NNW-SSE. Several of the faults are seismically active and/or have geomorphic evidence for Holocene slip. None of the faults affects the GPS-derived regional velocity field, indicating active slip rates are ≤2 mm yr −1 . We estimate total offsets for these faults from displaced geological and geomorphic markers, based on observations from satellite imagery, digital topography, geology maps and our own fieldwork observations, and combine these results with published estimates for fault displacement. Total right-lateral offset of the Dehu,

Mnin restraining stepover – evidence of significant Cretaceous–Cenozoic dextral strike-slip faulting along the Teisseyre-Tornquist Zone?

“…The estimated total offsets along the Indes and the Qom-Zefreh faults are approximately 40-50 km (Allen et al 2011).…”

Zagros orogeny: a subduction-dominated process

“…Modified after Aghanabati & Rezai (2009). (1) across-range shortening in the Zagros orogen and in far-field domains (Alborz, Kopet Dagh) at rates of 5 ± 2 mm yr −1 (McClusky et al 2000;Vernant et al 2004;Walpersdorf et al 2006;Masson et al 2007). Deformation was concentrated in the Zagros and the Alborz since Pliocene time at least (Oveisi et al 2009;Allen et al 2011) at a probably constant rate over the last 5 Ma . Out of the ∼ 2 cm yr −1 of overall orogen-normal shortening component, two thirds are taken up in the Zagros foldand-thrust belt (ZFTB) and one third in the Alborz, with domains such as the SSZ behaving more rigidly (Masson et al 2007).…”

“…The predominance of N-S dextral strike-slip faults to the east of the Kazerun-Doruneh faults could correspond to Iran moving north with respect to stable Afghanistan and/or to the existence of a somewhat freer boundary in the still subducting Makran region (at least before Pliocene time; Allen et al 2011;Regard et al 2010;Smit et al 2010b). Some of these major faults represent long-lived structures, such as the MRF or the Neh fault, which both reactivate suture zones (Talebian & Jackson, 2002;Walker et al 2009).…”

“…Yet, despite a wealth of recent data on GPS displacements, active deformation and kinematics (e.g. Vernant et al 2004;Walker, 2006;Le Dortz et al 2009;Allen et al 2011;Reilinger & McClusky, 2010) or on the tectonosedimentary record (e.g. Sherkati, Letouzey & Frizon de Lamotte, 2006;Mouthereau et al 2007;Homke et al 2009Homke et al , 2010, the Zagros orogen remains much less documented than its adjacent counterparts (the Himalayas, Turkey or the Alps).…”

Petrogenesis of mafic collision zone magmatism: The Armenian sector of the Turkish–Iranian Plateau

“…Plate convergence and compression continue today, focussed on the plateau margins in the Zagros, Greater Caucasus, Alborz and Kopeh Dagh ranges, whilst the interior of the plateau sits at~1-2 km above sea level. Internal plateau deformation occurs typically along strike-slip fault systems, but at rates ≤2 mm/yr, such that the regional GPS-derived velocity field is not affected (Vernant et al, 2004;Allen et al, 2011;Karakhanian et al, 2013). Thrust seismicity is confined to strike-slip fault terminations, and there is no significant extension within the plateau interior (Jackson et al, 1995).…”