Manuel Berberian

Bio: Manuel Berberian is an academic researcher. The author has contributed to research in topics: Geology & Continental crust. The author has an hindex of 2, co-authored 2 publications receiving 2403 citations.

Towards a paleogeography and tectonic evolution of Iran

Abstract: Maps of the paleography of Iran are presented to summarize and review the geological evolution of the Iranian region since late Precambrian time On the basis of the data presented in this way reconstructions of the region have been prepared that take account of the known major movements of continental masses These reconstructions, which appear at the beginning of the paper, show some striking features, many of which were poorly appreciated previously in the evolution of the region They include the closing of the 'Hercynian Ocean' by the northward motion of the Central Iranian continental fragment(s), the apparently simultaneous opening of a new ocean ('the High-Zagros Alpine Ocean') south of Iran, and the formation of 'small rift zones of oceanic character' together with the attenuation of continental crust in Central IranWith the disappearance of the Hercynian Ocean, the floor of the High-Zagros Alpine Ocean started to subduct beneath southern Central Iran and apparently disappeared by Late Cretaceou

The southern Caspian: A compressional depression floored by a trapped, modified oceanic crust

Abstract: The south Caspian intracontinental depression, floored by oceanic basement, is a relatively stable block, with minor deformation, surrounded by active fold-thrust belts of arcuate form (Talesh, Alb...

Active tectonics of the Alpine—Himalayan Belt between western Turkey and Pakistan

Abstract: Summary. Over 80 new fault plane solutions, combined with satellite imagery as well as both modern and historical observations of earthquake faulting, are used to investigate the active tectonics of the Middle East between western Turkey and Pakistan. The deformation of the western part of this region is dominated by the movement of continental material laterally away from the Lake Van region in eastern Turkey. This movement helps to avoid crustal thickening in the Van region, and allows some of the shortening between Arabia and Eurasia to be taken up by the thrusting of continental material over oceanic-type basement in the southern Caspian, Mediterranean, Makran and Black Sea. Thus central Turkey, bounded by the North and East Anatolian strike-slip faults, is moving west from the Van region and overrides the eastern Mediterranean at two intermediate depth seismic zones: one extending between Antalya Bay and southern Cyprus, and the other further west in the Hellenic Trench. The motion of northern Iran eastwards from the Van region is achieved mainly by a conjugate system of strike-slip faults and leads to the low angle thrusting of Iran over the southern Caspian Sea. The seismicity of the Caucasus shows predominantly shortening perpendicular to the regional strike, but there is also some minor elongation along the strike of the belt as the Causcasus overrides the Caspian and Black Seas. The deformation of the eastern part of this region is dominated by the shortening of Iran against the stable borders of Turkmenistan and Afghanistan. The north-east direction of compression seen in Zagros is also seen in north-east Iran and the Kopet Dag, where the shortening is taken up by a combination of strike-slip and thrust faulting. Large structural as well as palaeomagnetic rotations are likely to have occurred in NE Iran as a result of this style of deformation. North-south strike-slip faults in southern Iran allow some movement of material away from the collision zone in NE Iran towards the Makran subduction zone, where genuinely intermediate depth seismicity is seen. Within this broad deforming belt large areas, such as central Turkey, NW Iran (Azerbaijan), central Iran and the southern Caspian, appear to be almost aseismic and therefore to behave as relatively rigid blocks surrounded by active belts 200-300 km wide. The motion of these blocks can usefully be described by poles of rotation. The poles presented in this paper predict motions consistent with those observed and also predict the opening of the Gulf of Iskenderun NE of Cyprus, the change within the Zagros mountains from strike-slip faulting in the NW to intense thrusting in the SE, and the relatively feeble seismicity in SE Iran (Baluchistan). This description also explains why the north-south structures along the Iran-Afghanistan border do not cut the east-west ranges of the Makran. Within the active belts surrounding the relatively aseismic blocks a continuum approach is needed for a description of the deformation, even though motions at the surface may be concentrated on faults. The evolution of fault systems within the active zones is controlled by geometric constraints, such as the requirement that simultaneously active faults do not, in general, intersect. Many of the active processes discussed in this paper, particularly large-scale rotations and lateral movement along the regional strike, are likely to have caused substantial complexities in older mountain belts and should be accounted for in any reconstructions of them.

Present‐day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman

Abstract: SUMMARY A network of 27 GPS sites was implemented in Iran and northern Oman to measure displacements in this part of the Alpine‐Himalayan mountain belt. We present and interpret the results of two surveys performed in 1999 September and 2001 October. GPS sites in Oman show northward motion of the Arabian Plate relative to Eurasia slower than the NUVEL-1A estimates (e.g. 22 ± 2m m yr −1 at N8 ◦ ± 5 ◦ E instead of 30.5 mm yr −1 at N6 ◦ E at Bahrain longitude). We define a GPS Arabia‐Eurasia Euler vector of 27.9 ◦ ± 0.5 ◦ N, 19.5 ◦ ± 1.4 ◦ E, 0.41 ◦ ± 0.1 ◦ Myr −1 . The Arabia‐Eurasia convergence is accommodated differently in eastern and western Iran. East of 58 ◦ E, most of the shortening is accommodated by the Makran subduction zone (19.5 ± 2m m yr −1 ) and less by the Kopet-Dag (6.5 ± 2m m yr −1 ). West of 58 ◦ E, the deformation is distributed in separate fold and thrust belts. At the longitude of Tehran, the Zagros and the Alborz mountain ranges accommodate 6.5 ± 2m m yr −1 and 8 ± 2m m yr −1 respectively. The right-lateral displacement along the Main Recent Fault in the northern Zagros is about 3 ± 2m m yr −1 , smaller than what was generally expected. By contrast, large rightlateral displacement takes place in northwestern Iran (up to 8 ± mm yr −1 ). The Central Iranian Block is characterized by coherent plate motion (internal deformation < 2m m yr −1 ). Sites east of 61 ◦ E show very low displacements relative to Eurasia. The kinematic contrast between eastern and western Iran is accommodated by strike-slip motions along the Lut Block. To the south, the transition zone between Zagros and Makran is under transpression with right-lateral displacements of 11 ± 2m m yr −1 .

Convergence history across Zagros (Iran): constraints from collisional and earlier deformation

Abstract: The Zagros orogen provides a unique opportunity within the Alpine system to evaluate the interplay between a young Tertiary collision and earlier subduction/obduction processes. Within the Crush zone and the Sanandaj–Sirjan (internal) zone separating the Zagros Fold belt from Central Iran, we document several major tectonic events taking place at the end of the Cretaceous, of the Eocene and from the Mio–Pliocene onwards (ca. <20–15 Ma). Contrary to recent interpretations, our data (cross-sections and description of the overall deformation style) strongly suggest that the Main Zagros Thrust (MZT) is deeply rooted, possibly to Moho depths, and that the suture zone effectively runs along the MZT. Field observations show that the final resorption of the oceanic domain took place slightly after 35 Ma and that collision must have started before ca. 23–25 Ma in northern Zagros. The shortening rate across the Crush zone since the Mid-Miocene (20–15 Ma) is estimated at a minimum 3–4 mm/year. Shear movements in the Crush zone during the Eocene–Oligocene period and extensional/strike-slip movements in the internal zones during the late Cretaceous point to an oblique setting early in the convergence history. A geotectonic scenario for convergence from the time of obduction to the present is finally proposed.