scholarly journals Mechanical contrast and asymmetric distribution of crustal deformation across plate boundaries: Insights from the northern Dead Sea fault system

Geology ◽  
2020 ◽  
Author(s):  
Neta Dembo ◽  
Roi Granot ◽  
Yariv Hamiel

The distribution of permanent deformation near strike-slip plate boundaries and the underlying controlling variables are commonly poorly understood. Here we examine the crustal deformation across the northern Dead Sea fault system based on paleomagnetic observations and mechanical modeling. We focus our investigation on the region of the Lebanese restraining bend where the fault system strikes obliquely to the general Sinai-Arabia plate motion. We construct a series of crustal elasto-plastic models in which kinematics is based on geodetic measurements, and the geometry of the plate boundary is constrained by gravity data. Both the observed regional vertical axis rotations and the model results display significant counterclockwise rotations (as much as ~50°) confined to the northern Sinai microplate located west of the bend. On the other hand, relatively minor rotations (<~10°) are displayed for the adjacent Arabian plate. Our results, validated by structural evidence, suggest that the northern Sinai microplate is mechanically weaker than the adjacent crust of the Arabian plate. This mechanical contrast, along with the oblique convergence and change of slip rate along the Dead Sea fault system, is required to simulate the observed rotations. We propose that the crustal mechanical contrast across plate boundaries is a key parameter responsible for the distribution pattern of permanent vertical axis rotations.

1984 ◽  
Vol 121 (6) ◽  
pp. 577-587 ◽  
Author(s):  
P. E. R. Lovelock

AbstractThe structure of the northern part of the Arabian platform is reviewed in the light of hitherto unpublished exploration data and the presently accepted kinematic model of plate motion in the region. The Palmyra and Sinjar zones share a common history of development involving two stages of rifting, one in the Triassic–Jurassic and the other during late Cretaceous to early Tertiary times. Deformation of the Palmyra zone during the Mio-Pliocene is attributed to north–south compression on the eastern block of the Dead Sea transcurrent system which occurred after continental collision in the north in southeast Turkey. The asymmetry of the Palmyra zone is believed to result from northward underthrusting along the southern boundary facilitated by the presence of shallow Triassic evaporites. An important NW-SE cross-plate shear zone has been identified, which can be traced for 600 km and which controls the course of the River Euphrates over long distances in Syria and Iraq. Transcurrent motion along this zone resulted in the formation of narrow grabens during the late Cretaceous which were compressed during the Mio-Pliocene. To a large extent, present day structures in the region result from compressional reactivation of old lineaments within the Arabian plate by the transcurrent motion of the Dead Sea fault zone and subsequent continental collision.


2021 ◽  
Author(s):  
Matthieu Ribot ◽  
Yann Klinger ◽  
Edwige Pons-Branchu ◽  
Marthe Lefevre ◽  
Sigurjón Jónsson

<p>Initially described in the late 50’s, the Dead Sea Fault system connects at its southern end to the Red Sea extensive system, through a succession of left-stepping faults. In this region, the left-lateral differential displacement of the Arabian plate with respect to the Sinai micro-plate along the Dead Sea fault results in the formation of a depression corresponding to the Gulf Aqaba. We acquired new bathymetric data in the areas of the Gulf of Aqaba and Strait of Tiran during two marine campaigns (June 2018, September 2019) in order to investigate the location of the active faults, which structure and control the morphology of the area. The high-resolution datasets (10-m posting) allow us to present a new fault map of the gulf and to discuss the seismic potential of the main active faults.</p><p>We also investigated the eastern margin of the Gulf of Aqaba and Tiran island to assess the vertical uplift rate. To do so, we computed high-resolution topographic data and we processed new series of U-Th analyses on corals from the uplifted marine terraces.</p><p>Combining our results with previous studies, we determined the local and the regional uplift in the area of the Gulf of Aqaba and Strait of Tiran.</p><p>Eventually, we discussed the tectonic evolution of the gulf since the last major change of the tectonic regime and we propose a revised tectonic evolution model of the area.</p><p> </p>


2021 ◽  
Author(s):  
Jakub Fedorik ◽  
Francesco E. Maesano ◽  
Abdulkader M. Alafifi

<p>Strike-slip structures are rarely validated because commonly used 2D restoration techniques are not applicable. Here we present the results of 3D numerical simulation of the restraining bends in Lebanon using boundary element methods of fault deformation implemented in MOVE™. The Lebanon restraining bend is the largest transpressional feature along the Dead Sea Transform (DST), and consists of two mountain ranges: Mount Lebanon on the west, dominated by the active Yammouneh fault, and the Anti-Lebanon Range to the east, influenced by the Serghaya and other faults. We built a new 3D geometrical model of the fault surfaces based on previous mapping of faults onshore and offshore Lebanon, complemented by interpretation of satellite images and DEM, and analogy with experimental models of restraining bend or transpressional structures. The model was simulated in response to the regional stress produced by the left-lateral displacement of the Arabian plate. The simulation accurately predicted the shape and magnitude of positive and negative topographic changes and faults slip directions throughout Lebanon. Furthermore, this simulation supports the hypothesis that the formation of the Anti-Lebanon Range was influenced by the intersection of the DST with the older Palmyrides belt, resulting in failed restraining bend. In contrast, the structure of Mt. Lebanon is similar to laboratory experiments of a restraining bend without inheritance. In addition, our simulation presents an approach of how strike-slip structural models may be validated in areas where subsurface data are limited.</p>


2020 ◽  
Vol 221 (3) ◽  
pp. 1913-1940
Author(s):  
Francisco Gomez ◽  
William J Cochran ◽  
Rayan Yassminh ◽  
Rani Jaafar ◽  
Robert Reilinger ◽  
...  

SUMMARY A comprehensive GPS velocity field along the Dead Sea Fault System (DSFS) provides new constraints on along-strike variations of near-transform crustal deformation along this plate boundary, and internal deformation of the Sinai and Arabian plates. In general, geodetically derived slip rates decrease northwards along the transform (5.0 ± 0.2 to 2.2 ± 0.5 mm yr−1) and are consistent with geological slip rates averaged over longer time periods. Localized reductions in slip rate occur where the Sinai Plate is in ∼N–S extension. Extension is confined to the Sinai side of the fault and is associated with prominent changes in transform geometry, and with NW–SE striking, left-lateral splay faults, including the Carmel Fault in Israel and the Roum Fault in Lebanon. The asymmetry of the extensional velocity gradients about the transform reflects active fragmentation of the Sinai Plate along the continental margin. Additionally, elastic block modelling of GPS velocities requires an additional structure off-shore the northern DSF segment, which may correspond with a fault located along the continental margin, suggested by prior geophysical studies.


1998 ◽  
Author(s):  
Uri S. ten Brink ◽  
M. Rybakov ◽  
A. Al-Zoubi ◽  
M. Hassouneh ◽  
A. Batayneh ◽  
...  

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