Structures associated with extensional tectonics in the Suez rift

Chenet, P.; Colletta, B.; Letouzey, J.; Desforges, G.; Ousset, E.; Zaghloul, E. A.

doi:10.1144/gsl.sp.1987.028.01.36

Cited by 21 publications

(13 citation statements)

References 5 publications

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“…These longitudinal faults dip generally between 30° to 60° while transverse faults dip more steeply. Horizontal offsets along the transverse faults are mainly related to the horizontal transverse component of the throw on the longitudinal faults and not due to any older event, such as the NW-SE Eocene compression (Chenet et al, 1987).…”

Section: S Rmentioning

confidence: 98%

Seismological and GPS constraints on Sinai sub-plate motion along the Suez rift

2008

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This work presents new seismological and Global Positioning System (GPS) resultsaimed at understanding the nature and rate of strain associated with the opening of the Suez rift that separates the Sinai sub-plate from the African plate. The Sinai sub-plate has played a significant role in the tectonic evolution of the northern Red Sea and the Eastern Mediterranean region. Most small, moderate and large earthquakes occur within belts associated with the geologically documented borders of this sub-plate including the Dead Sea fault (DSF) system in the east, the Cyprian arc (CA) in the north, and the Suez rift (SR) to the southwest. The DSF and CA are well defined; however, the SR is only partially defined. Earthquake foci distribution supports the idea that the SR is seismically active, and this earthquake activity cannot be ignored throughout the kinematics evaluation of northern Red Sea region. The earthquake activity is relatively higher in the southern part of the SR and gradually decreases northward. The high seismicity is mainly attributed to the presence of the Sinai triple junction. Earthquake focal mechanisms in the SR are dominated by oblique normal faulting with left-lateral strike-slip components on NW trending fault planes consistent with regional kinematics. The extensional semi-principal stress axes derived from fault plane solutions are oriented NNE-SSW in good agreement with the current stress field obtained from borehole breakouts along the SR as well as results from GPS surveying. Recent survey-mode GPS observations provide evidence for coherent northerly motion of the Sinai sub-plate that varies between 2 and 5 mm/yr. Moreover, strain analysis indicates that the southern SR is dominated by extension while its northern segment is characterized by constriction, inconsistent with earthquake focal mechanisms and regional tectonic models. The overall northward motion of the Sinai subplate indicates that slab-pull rather than ridge-push is the dominant force controlling regional kinematics. Based on the low rate of extension and lack of oceanic crust, the SR can be considered an incipient plate boundary between the Sinai sub-plate and the Nubian plate. K e y w o r d s : earthquakes, focal mechanisms, GPS, Sinai sub-plate, Suez rift Stud. Geophys. Geod., 52 (2008), 397−412 397

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Section: S Rmentioning

confidence: 98%

Seismological and GPS constraints on Sinai sub-plate motion along the Suez rift

2008

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“…14). Block faulting and opening of the Gulf of Suez began in the late Oligocene (Robson, 1971;Scott and Govean, 1984;Sellwood and Netherwood, 1984;Chenet et al, 1987) in response to northeast-southwest extension (Angelier, 1985;Lyberis, 1988). Opening of the Gulf of Suez largely ceased during Pliocene time when extension of the northern Red Sea was taken up by the sinistral, Dead Sea-Aqaba transform fault system (Garfunkel, 1981).…”

Section: Low-strain Riftsmentioning

confidence: 99%

“…14) (Chenet and Letouzey, 1983;Schamel and Wise, 1984;Ott d'Estevou et al, 1986;Chenet et al, 1987), where major, rift-parallel normal faults curve into transfer segments and define listric, spoon-shaped fault geometries with oblique-slip on transverse segments. In addition, northeast-striking, high-angle transfer faults, with highly variable slip components, characterize the southwestern extension of the Morgan accommodation zone on the western margin of the gulf, where opposing normal-fault systems overlap and terminate across a narrow (~5 km wide) zone (Coffield and Schamel, 1989).…”

Section: S In Is Tr a L S Y N Th E Ti C T Z S Y N Th E Ti C A Z S Y Nmentioning

confidence: 99%

The role of accommodation zones and transfer zones in the regional segmentation of extended terranes

Faulds¹,

Varga²

1998

Accommodation Zones and Transfer Zones; The Regional Segmentation of the Basin and Range Province

178

176

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All normal-fault systems must terminate both along and orthogonal to strike. As many as four terminations may be associated with a single culmination. Most normalfault systems terminate in either transfer zones or accommodation zones. In the nongenetic classification proposed here, transfer zones are defined as discrete zones of strike-slip and oblique-slip faulting that generally trend parallel to the extension direction and typically facilitate a transfer of strain between extended domains arranged in an en echelon pattern. Accommodation zones are belts of overlapping fault terminations and can separate either systems of uniformly dipping normal faults or adjacent domains of oppositely dipping normal faults. They can trend parallel, perpendicular, or oblique to the extension direction. A review of variously extended continental provinces and passive continental margins reveals that the style of deformation within transfer and accommodation zones is independent of the magnitude of extension.Strike-slip and oblique-slip faults within transfer zones are closely linked kinematically with major normal faults within the extended terranes. Transfer zones linking spatially separated loci of extension display along-strike variations in both magnitude and sense of motion, whereas local normal and reverse faults may develop in the vicinity of releasing and restraining fault bends. Strain within accommodation zones is transmitted directly between normal-fault systems, geometries being controlled by the amount of overlap between and relative dip direction of competing sets of normal faults. Antithetic accommodation zones develop between oppositely dipping normal-fault systems, whereas synthetic accommodation zones occur between similarly dipping systems. In the synthetic zone, relay ramps commonly connect the hanging wall of one fault to the footwall of another fault and trend obliquely in zones that have significantly overlapping normal faults but transversely (parallel to extension direction) in zones that have minimal overlap. Antithetic zones exhibit a wider variety of geometries, including (1) strike-parallel (parallel to trend of rift) anticlines and synclines between normal-fault systems having complete overlap that dip toward and away from one another, respectively, (2) obliquely trending anticlines and synclines in areas of partial fault overlap, and (3) transverse zones between minimally overlapping fault systems. The distinction between the strike-parallel and transverse accommodation zones is scale dependent; large strike-parallel segments are characterized by finescale offsets of hingelines along small transverse segments, and large transverse zones Faulds, J. E., and Varga, R. J., 1998, The role of accommodation zones and transfer zones in the regional segmentation of extended terranes, in Faulds, J. E., and Stewart, J. H., eds., Accommodation Zones and Transfer Zones: The Regional Segmentation of the Basin and Range Province: Boulder, Colorado, Geological Society of America Special Paper 323. 1 on March 24, 2...

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“…Hanging-wall deformation in extensional settings has the potential to create complex syn-extensional structures such as folds and faults [46][47][48][49][50][51]. It is commonly accepted that movements on the fault planes of the normal faults result in longitudinal and transverse folds that are parallel and perpendicular to the associated normal faults, respectively [4].…”

Section: Mechanism/origin Of Foldingmentioning

confidence: 99%

Geometry and origin of folding in the Neogene sediments of the Gediz Graben, western Anatolia, Turkey

Sözbi̇li̇r

2002

Geodinamica Acta

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A close relationship between formation of approximately upright folds with axes normal to the extension direction and ramp/flat extensional geometries is established for well exposed Neogene syn-extensional rocks on the presently low-angle Gediz detachment fault. along the southern margin of the Gediz Graben region of western Anatolia, Turkey. Three unconformity-bounded sedimentary sequences and several metamorphic extensional allochthons were mapped in the upper-plate of the Gediz detachment. The oldest sedimentary sequence consists of deformed and folded strata of sandstones and conglomerates that are regarded as being deposited in a supra-detachment basin during the Miocene-Early Pliocene. This unit rests unconformably on the extensional allochthonous, but directly in fault contact with the lower-plate mylonitic rocks. The younger slightly tilted Late Pliocene-Pleistocene sedimentary sequences are post-detachment units that are controlled by EW-trending high-angle normal faults. The youngest alluvium comprises the undeformed present-day basin fill of the Gediz Graben. The supra-detachment sedimentary rocks contain a number of kilometric-scale longitudinal folds that are nearly parallel to the east-west-trending fault system of the Gediz Graben. The folds have a steeply inclined bisecting surface, an interlimb angle of 130-150°, and a plunge of< 10°. These folds may be interpreted to form as a result of bending in the underlying Gediz detachment fault. The bending may have an alternation of ramp and flat geometries on which a hanging-wall syncline and rollover anticline formed, respectively. This study again shows the importance of local geology in understanding of some spectacular structures of the extensional basins.

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Structures associated with extensional tectonics in the Suez rift

Cited by 21 publications

References 5 publications

Seismological and GPS constraints on Sinai sub-plate motion along the Suez rift

Seismological and GPS constraints on Sinai sub-plate motion along the Suez rift

The role of accommodation zones and transfer zones in the regional segmentation of extended terranes

Geometry and origin of folding in the Neogene sediments of the Gediz Graben, western Anatolia, Turkey

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