Active crustal shortening in NE Syria revealed by deformed terraces of the River Euphrates

Abstract

The Africa–Arabia plate boundary comprises the Red Sea oceanic spreading centre and the left‐lateral Dead Sea Fault Zone (DSFZ); however, previous work has indicated kinematic inconsistency between its continental and oceanic parts. The Palmyra Fold Belt (PFB) splays ENE from the DSFZ in SW Syria and persists for ∼400 km to the River Euphrates, but its significance within the regional pattern of active crustal deformation has hitherto been unclear. We report deformation of Euphrates terraces consistent with Quaternary right‐lateral transpression within the PFB, indicating anticlockwise rotation (estimated as 0.3° Ma−1 about 36.0°N 39.8°E) of the block between the PFB and the northern DSFZ relative to the Arabian Plate interior. The northern DSFZ is shown to be kinematically consistent with the combination of Euler vectors for the PFB and the Red Sea spreading, resolving the inconsistency previously evident. The SW PFB causes a significant earthquake hazard, previously unrecognized, to the city of Damascus.

Late Cenozoic regional uplift and localised crustal deformation within the northern Arabian Platform in southeast Turkey: Investigation of the Euphrates terrace staircase using multidisciplinary techniques

“…This reversal in the sense of vertical crustal motion is widely recognised in fluvial sequences in the Arabian Platform (e.g. Demir et al, 2007bDemir et al, , 2008Abou Romieh et al, 2009;Bridgland et al, 2012-this issue); its cause is not established, although Westaway (2012-this issue) suggests a possible physical mechanism. Like for the Işık gravel, given the component of localised subsidence in synclinal areas such as Karababa Bridge, the thickness of aggradation will exceed the contemporaneous regional subsidence.…”

“…Reilinger et al, 2006) and too little information exists from the instrumental or historical seismicity. However, in NE Syria, Abou Romieh et al (2009) have documented active faulting affecting Euphrates terraces. Given that the Bozova Fault crosses the Euphrates valley within the present study region (Fig.…”

A numerical modelling technique that can account for alternations of uplift and subsidence revealed by Late Cenozoic fluvial sequences

“…Angled arrows correspond to the starts of phases of LCFF identified in uplift modelling by Demir et al (2007). Note that the Euphrates terrace deposits in this part of Syria are affected by active faulting as well as regional uplift (Litak et al, 1997;Abou Romieh et al, 2009); the precise height of any particular terrace thus varies with downstream location (see Abou Romieh et al, 2009, for long-profile projections of the terraces). Nonetheless, this composite transverse profile summarises the nature of this fluvial archive in a manner suitable to highlight the issues raised in the present study.…”

The River Orontes in Syria and Turkey: Downstream variation of fluvial archives in different crustal blocks

“…Recent interpretations of the regional kinematics (e.g. Westaway, 2004b;Gomez et al, 2006;Seyrek et al, 2008;Abou Romieh et al, 2009) require a component of crustal shortening in the crustal blocks alongside the active left-lateral faults forming the northern DSFZ. It is thus probable that any dip-slip fault in the Antakya area, away from the main left-lateral faulting, would be a reverse fault (cf.…”