A discussion on the structure and evolution of the Red Sea and the nature of the Red Sea, Gulf of Aden and Ethiopia rift junction - The structural pattern of the Afro-Arabian rift system in relation to plate tectonics

The structural pattern of the Afro-Arabian rift system suggests the influence of transcurrent faulting in the development of the main branches of the system, particularly along the Dead Sea rift, the Gulf of Suez and Red Sea, and the eastern rift of Africa. Geophysical evidence indicates that the Red Sea and Gulf of Aden formed as a result of the separation of the Arabian and African continental blocks. Previously determined rotation poles about which the blocks separated neglect some structural features of the region. A satisfactory refit of Arabia to Africa can­ not be made unless some relative movements of parts of the Africa block too place. It is proposed that dextral strike-slip movements took place between Africa and Arabia along the Red Sea and that sinistral strike-slip movements occurred along the Dead Sea rift. In addition, rotation of the E. Kenya-Somalia block east of the eastern rift of Africa took place. Structural and palaeomagnetic evidence supports such movements. The structural model is compatible with the observed tectonic pattern and provides a genetic link between the formation of the Red Sea, Gulf of Aden and the African rifts.

The meeting has promoted a valuable exchange of ideas between field geologists, geologists engaged in petroleum exploration in and around the Red Sea, and geophysicists who have undertaken land, airborne and marine surveys. The results are of fundamental interest in several fields. The ancient crystalline rocks, discussed by Brown and Beydoun, revealed little to suggest a control of the Red Sea geosuture by Precambrian structures. The old eugeosynclinal trough in Arabia perhaps trends N 30° W, but Brown had been unwilling to assign a direction to the postulated miogeosynclinal trough. The early sediments had been extensively annealed by metamorphism and by igneous intrusion on a large scale. It did not appear that an obvious case for the location of either the Red Sea or the Gulf of Aden along a pre-existing line of crustal weakness could be made out from the surface geology, though the case of the Dead Sea rift may be different.


Author(s):  
K. O. Emery ◽  
David Neev

The Dead Sea occupies a linear down-dropped region between two roughly parallel faults along the central segment of the major northsouth- trending crustal rift that extends about 1,100 km from the Red Sea through the Gulf of Elath to Turkey. This rift or geosuture separates the Arabian crustal sub-plate on the east from the Sinai one on the west. An origin as early as Precambrian is possible (Bender, 1974; Zilberfarb, 1978). Crystalline crust along the north-south trough of the Sinai sub-plate is about 40 km thick in contrast with a thickness of half as much above ridges along both flanks (Ginsburg and Gvirtzman, 1979). Toward the north the ridges appear to converge (Neev, Greenfield, and Hall, 1985). Since the Miocene period the Arabian plate has moved north about 105 km relative to the Sinai plate. This sort of crustal movement along either side of a rift is termed strike-slip faulting. One result of it was the opening of the Red Sea relative to the Gulf of Suez. The Dead Sea graben, a down-dropped block between two roughly parallel faults, occupies the central segment of the long crustal rift. The boundary between these is rather sharp along the east shore of the sea (Frieslander and Ben-Avraham, 1989). Actual post-Miocene movement was along not just a single major fault but was distributed among numerous sub-parallel faults that form a 100-km-wide belt in which movements were transferred from one fault to another (Eyal et al., 1981; Gilat and Honigstein, 1981). Recent movements have occurred along the south segment of the north-south-trending Arava fault south of the Amazyahu transverse fault (Zak and Freund, 1966). These strike-slip movements probably did not continue after Miocene along the main East fault of the Dead Sea, which is the north extension of the Arava wrench fault. In contrast, recent movements have been present along the north-northeast- trending Jordan or Dead Sea fault (Ben-Menahem et al., 1977, fig. 1). The movements extend south from east of Jericho in the north along the base of the west submarine slope of the sea and the elongate salt diapir of Mount Sedom as far as the Amazyahu fault in the south.


Recent surface and subsurface geological investigations in Israel and Jordan provide new data for the re-examination of Dubertret’s (1932) hypothesis of the left-hand shear along the Dead Sea rift. It is found that while none of the pre-Tertiary sedimentary or igneous rock units extend right across the rift, all of them resume a reasonable palaeographical configuration once the east side of the rift is placed 105 km south of its present position. It is therefore concluded that the 105 km post-Cretaceous, left-hand shear along the Dead Sea rift is well established. The 40 to 45 km offset of Miocene rocks and smaller offsets of younger features indicate an average shear movement rate of 0.4 to 0.6 cm a -1 during the last 7 to 10 Ma. Unfortunately, the 60 km pre-Miocene movement cannot be dated yet. Along the Arava and Gulf of Aqaba and in Lebanon the shear is divided over a wide fault zone within and outside the rift.


The Red Sea structure as well as the appurtenant Dead Sea structure originated at the end of the Precambrian, as shown by many established observations. Their latest, Neogene phases of evolution have often too exclusively been considered to explain the present-day layout. Many peculiar field features, which are cited as evidence for a northward drift of the Arabian peninsula (relative to Palestine and Sinai), may as well be explained by vertical movements. A 107 km northward drift of the Arabian peninsula, of which 40 km was in Pleistocene times, as asserted by Quennell and Freund, is not confirmed by recent surveys in the Dead Sea area and is inconsistent with the stratigraphy and the structure of Lebanon and Syria: therefore it should not be taken as geologically definitely proven and as leading to conclusions as to the Red Sea.


Author(s):  
Roey Shimony ◽  
Zohar Gvirtzman ◽  
Michael Tsesarsky

ABSTRACT The Dead Sea Transform (DST) dominates the seismicity of Israel and neighboring countries. Whereas the instrumental catalog of Israel (1986–2017) contains mainly M<5 events, the preinstrumental catalog lists 14 M 7 or stronger events on the DST, during the past two millennia. Global Positioning System measurements show that the slip deficit in northern Israel today is equivalent to M>7 earthquake. This situation highlights the possibility that a strong earthquake may strike north Israel in the near future, raising the importance of ground-motion prediction. Deep and narrow strike-slip basins accompany the DST. Here, we study ground motions produced by intrabasin seismic sources, to understand the basin effect on regional ground motions. We model seismic-wave propagation in 3D, focusing on scenarios of Mw 6 earthquakes, rupturing different active branches of the DST. The geological model includes the major structures in northern Israel: the strike-slip basins along the DST, the sedimentary basins accompanying the Carmel fault zone, and the densely populated and industrialized Zevulun Valley (Haifa Bay area). We show that regional ground motions are determined by source–path coupling effects in the strike-slip basins, before waves propagate into the surrounding areas. In particular, ground motions are determined by the location of the rupture nucleation within the basin, the near-rupture lithology, and the basin’s local structure. When the rupture is located in the crystalline basement or along material bridges connecting opposite sides of the fault, ground motions behave predictably, decaying due to geometrical spreading and locally amplified atop sedimentary basins. By contrast, if rupture nucleates or propagates into shallow sedimentary units of the DST strike-slip basins, ground motions are amplified within, before propagating outside. Repeated reflections from the basin walls result in a “resonant chamber” effect, leading to stronger regional ground motions with prolonged durations.


Tectonics ◽  
1990 ◽  
Vol 9 (6) ◽  
pp. 1421-1431 ◽  
Author(s):  
H. Ron ◽  
A. Nur ◽  
Y. Eyal

2004 ◽  
Vol 141 (5) ◽  
pp. 565-572 ◽  
Author(s):  
YUVAL BARTOV ◽  
AMIR SAGY

A newly discovered active small-scale pull-apart (Mor structure), located in the western part of the Dead Sea Basin, shows recent basin-parallel extension and strike-slip faulting, and offers a rare view of pull-apart internal structure. The Mor structure is bounded by N–S-trending strike-slip faults, and cross-cut by low-angle, E–W-trending normal faults. The geometry of this pull-apart suggests that displacement between the two stepped N–S strike-slip faults of the Mor structure is transferred by the extension associated with the normal faults. The continuing deformation in this structure is evident by the observation of at least three deformation episodes between 50 ka and present. The calculated sinistral slip-rate is 3.5 mm/yr over the last 30 000 years. This slip rate indicates that the Mor structure overlies the currently most active strike-slip fault within the western border of the Dead Sea pull-apart. The Mor structure is an example of a small pull-apart basin developed within a larger pull-apart. This type of hierarchy in pull-apart structures is an indication for their ongoing evolution.


Subject The implications of the Red Sea-Dead Sea plan. Significance Israel and Jordan on February 26 signed an agreement to facilitate water-sharing and address the depletion of the Dead Sea, which is receding at a rate of about a metre per year. The 900 million dollar World Bank-sponsored 'Seas Canal' deal consists of two main aspects: local water exchange deals, with Jordan providing Israel with desalinated water from Aqaba in exchange for bluewater from the Sea of Galilee in the north; and saltwater transfer from the Red Sea to the Dead Sea. The Palestinian Authority is not party to the agreement, and awaits a separate deal with Israel. Impacts Prospects for Palestinian-Israeli water negotiations have drastically decreased. Jordan will still need to agree further desalination and cooperation deals in order to meet demand. Water saving efforts will be pushed aside in favour of much more costly desalination. Desalination powered by burning fossil hydrocarbons accelerates global warming.


2016 ◽  
Vol 401 ◽  
pp. 123-131 ◽  
Author(s):  
Engin Meriç ◽  
Ertuğ Öner ◽  
Niyazi Avşar ◽  
Atike Nazik ◽  
Hakan Güneyli ◽  
...  
Keyword(s):  
Red Sea ◽  
Dead Sea ◽  

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