The transition between Makran subduction and the Zagros collision: recent advances in its structure and active deformation

Abstract

SE Iran is the site of a rare case of young transition between subduction and collision. We have synthesized recent results in geodesy, tectonics, seismology and magnetism to help understand the structure and kinematics of the Zagros–Makran transition. Surface observations (tectonics, magnetism and geodesy) indicate a transpressive discontinuity consisting of several faults striking obliquely to the convergent plate motion, whereas deeper observations (seismology) support a smooth transition across the fault system. No lithospheric transform fault has been created, although the transition already behaves like a major boundary in terms of tectonic style, seismic structure, lithology and magnetism. The Zendan–Minab–Palami fault system consists of several faults that accommodate a transpressive tectonic regime. It is the surface expression of a southward propagation of the north–south-trending right-lateral strike-slip fault system of Jiroft–Sabzevaran. Within each system the numerous faults will coalesce into a single, lithospheric, wrench fault.

Active faulting of the southeastern-most Zagros (Iran): Microearthquake seismicity and crustal structure

“…This pattern is different from what is observed in the Zagros Fold Belt where hypocenters are confined to the upper crust (8-15 km) located beneath the thick layer of sediments (Tatar et al, 2004). This trend is also observed in the north of the MZRF, around Tiab (Gholamzadeh et al, 2009) and east of the Zendan-Minab-Palami fault system in the transition zone between the Zagros and the Makran (Yamini-Fard et al, 2007;Regard et al, 2010). It suggests that some part of the observed seismicity is related to slip on a major intracrustal thrust fault.…”

“…The inset shows the geographical setting and the box inside that includes Khurgu area. results in geodesy, tectonic and seismology confirm that the transition between the Zagros collision and subduction in the Makran is a progressive transition located in the lower crust and is not a sharp lithospheric-scale transform fault (Regard et al, 2004(Regard et al, , 2010Yamini-Fard et al, 2007). Microseismicity and the instrumental record confirm the lack of seismicity related to the ZMP fault zone (Yamini-Fard et al, 2007) although GPS measurement by Peyret et al (2009) shows about 10 mm/yr fault slip.…”

“…Moreover, studies based on magnetic data show rotations that are clockwise to the east and anticlockwise to the west of the ZMP, suggesting an indentor role for the Musandam peninsula (Aubourg et al, 2004). However, GPS measurements do not suggest any rigid indentation in the area that must create a left-lateral shear (Bayer et al, 2006;Regard et al, 2010). Regard et al (2010) considered second order indentation of Musandam and suggest that the topographic Musandam high causes the Fars Arc curvature.…”

“…The ZMP fault system, accommodating a transpressive teconic regime, is a southward propagation of the north-trending rightlateral strike-slip fault system of Jiroft-Sabzevaran (Regard et al, 2010). Geological observations and recent GPS measurements indicate that about 15 mm/yr of relative motion between continental collision and oceanic subduction is accommodated in the transition zone (Bayer et al, 2006;Regard et al, 2005Regard et al, , 2010. Recent (Talebian and Jackson, 2004;Engdahl et al, 2006).…”

A Study on Tectonic and Sedimentology in Order to Fault Rupture Potential in Coasts the Makran Sea

“…This subduction is associated with an accretionary wedge of sediments which has developed since the Cenozoic [2] [3]. To the west, the Makran Trench is connected by the Minab Fault system to the Zagros fold and thrust belt [4]. To the east, the Makran Trench is bounded by the transpressional strike-slip Oranch-Nal and Chaman Faults, which connect to the Himalayan orogeny.…”