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 existence of transform faults in the Red Sea depression

1970 ◽  
Vol 267 (1181) ◽  
pp. 407-408 ◽  
Keyword(s):  
Red Sea ◽  
Gulf Of Aden ◽  
Transform Fault ◽  
Basement Complex ◽  
Transform Faults ◽  
Left Handed ◽  
The World ◽  
History Of ◽  
First Motion ◽  
Earthquake Mechanism

Girdler (1968, pp. 1102-1105) has suggested that transform faults may exist in the Red Sea depression. A possible left-handed transform fault, trending at 050°, and centred on 19°N 39°E was plotted (Girdler 1968, fig. 1). This is supposed to offset the axial trough, and run on to the land, where it is shown displacing the ‘marginal structure lines’ and the Mesozoic and Tertiary sedimentary/Basement Complex contact by about 50 km. Girdler (1968) cites Sykes (in History of the Earth's crust , Nasa, Symposium) as providing sup­porting first motion evidence of transform movement along this proposed fault. However Isaacs, Sykes & Oliver (1968, fig. 5) show a left-handed transform ‘earthquake mechanism’ bearing 020° for a centre associated with the axial trough at 17°N, 40° 30' E. Because of the proximity of these centres, the 30° difference in trend, and the scarcity of Red Sea earthquake data, the question arises are Girdler and Isaacs et al . dealing with the same centres ? More data and an explanation are required as there are few places in the world where undisputed trans­form faults have been described from the land and sea. Girdler’s proposed transform fault is therefore extremely important both from a local Red Sea and a global structural view.

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 - Magnetic and gravity fields over the Red Sea

1970 ◽  
Vol 267 (1181) ◽  
pp. 153-180 ◽  
Keyword(s):  
Red Sea ◽  
Gravity Anomalies ◽  
Gulf Of Aqaba ◽  
Second Phase ◽  
Gulf Of Aden ◽  
Horn Of Africa ◽  
Transform Faults ◽  
Gravity Fields ◽  
Anomaly Pattern ◽  
Separate Block

Strong magnetic anomalies associated with the axial trough of the Red Sea are considered to be related to a second phase of opening. Lack of magnetic expression of the first and wider separation is attributed to initial thinning and necking of the continental crust and, possibly, to a slow rate of spreading. The rise of the mantle during this first stage is reflected in the positive Bouguer gravity anomaly which extends over the whole Sea. A displacement of the magnetic anomaly pattern and a grouping of earthquake epicentres at latitude 19½° N delineates a transform fault. Futher offsets in the anomaly pattern between 19½° N and 23° N may be related to other transform faults presently inactive. If Sinai is treated as a separate block then the two-stage clockwise rotation of Africa to open the Red Sea leads to the southerly displacements of this block required by the geology. Negative gravity anomalies in the Gulf of Aqaba support the idea of a shear. A separate rotation of the Horn of Africa is believed to have contributed to the opening of the Gulf of Aden.

Chthamalid barnacles (Cirripedia: Thoracica) of the Persian Gulf and Gulf of Oman, Iran

2010 ◽  
Vol 91 (3) ◽  
pp. 745-753 ◽  
Author(s):  
Adnan Shahdadi ◽  
Alireza Sari
Keyword(s):  
Coastal Zone ◽  
Red Sea ◽  
Persian Gulf ◽  
Gulf Of Aden ◽  
Habitat Types ◽  
Gulf Of Oman ◽  
The World ◽  
The Persian Gulf ◽  
Key Characters

In the present study, chthamalid barnacles of the Persian Gulf and Gulf of Oman were collected from the coastal zone of Iran. Extensive collecting of different habitat types resulted in finding two species: Chthamalus barnesi and Microeuraphia permitini. In addition to the Persian Gulf and Gulf of Oman, the former species was also collected from the Red Sea and Gulf of Aden. Both species are described and compared for their key characters with some representative members of the genera from other parts of the world.

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 - Introductory remarks

1970 ◽  
Vol 267 (1181) ◽  
pp. 5-7 ◽  
Keyword(s):  
Red Sea ◽  
World Ocean ◽  
The Other ◽  
Rift System ◽  
Gulf Of Aden ◽  
Sea Floor ◽  
The Earth ◽  
The World ◽  
The Many ◽  
Sea Floor Spreading

The Red Sea Discussion Meeting originated in the desire of the other organizers to bring together as many as possible of the earth scientists who have been working recently in that area to examine the latest evidence and ideas on its structure and origin, to see how they accord with modern continental and sea-floor spreading concepts. The Red Sea, Gulf of Aden and Afar crustal depressions, now known to be continuous with the extension of the world ocean rift system, have been claimed as a manifestation of crustal separation, but some Earth scientists still consider that the evidence can be explained by less drastic crustal rifting. Definite solutions to the many outstanding problems were not expected but discussions would clearly assist further researches.

X V III. Discussion

1965 ◽  
Vol 258 (1088) ◽  
pp. 205-213 ◽  
Keyword(s):  
Red Sea ◽  
Continental Drift ◽  
Rift System ◽  
Gulf Of Aden ◽  
Vertical Movements ◽  
Red Sea Rift ◽  
Geological Features ◽  
Carlsberg Ridge ◽  
History Of ◽  
African Rift

We have heard many excellent arguments in favour of continental drift, based on the most recent results of studies of the ocean floors, the fit of the continents, the palaeomagnetic picture, and several instances of the relation between geological features and the supposed movement of the continents. It has struck me that these geological features are very restricted in number; they are either the oceanic rifts or wrench faults. Let us have a look first at the oceanic rifts. They are directly connected, through the Carlsberg Ridge and the Gulf of Aden with the Red Sea Rift and then through the Ethiopian faults with the famous African rifts. The history of the African rift system is relatively well known, and we know for certain that they represent principally vertical movements of the Earth’s crust, which have lasted at least from the Tertiary and probably since the Jurassic.

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 seismicity of the Red Sea, Gulf of Aden and Afar triangle

1970 ◽  
Vol 267 (1181) ◽  
pp. 49-74 ◽  
Keyword(s):  
Red Sea ◽  
Body Wave ◽  
Western Boundary ◽  
Earthquake Activity ◽  
Gulf Of Aden ◽  
Transform Faults ◽  
Fault Plane Solutions ◽  
Afar Depression ◽  
Sea Floor Spreading ◽  
Afar Triangle

The seismicity of the Red Sea, Gulf of Aden and Afar triangle has been studied for the period January 1953 through December 1968. Epicentres have been relocated using the method of joint Epicentral Deter­mination (Douglas 1967) and some fault plane solutions have been attempted. Magnitude-frequency studies indicate that with the present distribution of teleseismic stations, earthquakes with body wave magnitude m b ≽ 4.8 are well determined in this region. The study confirms that there is surprisingly little major earthquake activity in the northern part of the Red Sea. Between 19.5 and 21.0° N, there is a concentration of epicentres and some of these might be associated with an active NNE transform fault. In the southern part of the Red Sea, most of the epicentres are associated with the deep, axial trough, although some are associated with the western mar­gin, especially in the neighbourhood of the Gulf of Zula (15° N). Earthquake activity is confined to the centre of the Gulf of Aden with concentrations of epicentres occurring on or near to NNE transform faults. The seismically active zone continues westwards through the Gulf of Tadjoura and across the Afar depression to the western boundary scarp. There are no teleseismically recorded epicentres between latitudes 12.2 and 14.2° N. In general, most of the seismic activity occurs along the centres of the Red Sea and Gulf of Aden and this supports a sea-floor spreading mechanism for their origin. The number of plates involved is discussed.

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 Gulf of Suez: a brief review of stratigraphy and structure

1970 ◽  
Vol 267 (1181) ◽  
pp. 41-48 ◽  
Keyword(s):  
Red Sea ◽  
Upper Cretaceous ◽  
Hot Springs ◽  
Gulf Of Suez ◽  
Gulf Of Aden ◽  
Transform Faults ◽  
Clastic Sediments ◽  
Stratigraphic Record ◽  
Intrusive Activity

This paper gives a brief review of the main elements of the complex stratigraphy and structure of the Gulf of Suez, with an attempt to interpret or rather speculate on the role of lateral movements in its development. The stratigraphic record shows that the Gulf existed as a shallow embayment of the Tethys since at least the Carboniferous, and that a landmass lay at its southern end until upper Cretaceous. Predomi­nantly clastic sediments characterizing its early history changed to calcareous marine since the Cenoma­nian. Intensive faulting and subsidence, associated with volcanic and intrusive activity was evident since Upper Cretaceous, reached a maximum towards the end of Oligocene, continued through the Miocene and into the Pleistocene; hot springs are still active at present. Structurally the Gulf was divided by van der Ploeg into four provinces delineated by NNE—SSW trending ‘cross disturbances’. The four provinces appear to have formed two deep basins separated by two structural highs. It is speculated that the cross disturbances may represent transform faults between en échelon tension fissures (basins), produced as a result of a limited movement of Sinai towards the NNE relative to Africa, perhaps at a slower rate than the movement of Arabia.

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 evolution of the Gulf of Aden

1970 ◽  
Vol 267 (1181) ◽  
pp. 227-266 ◽  
Keyword(s):  
Red Sea ◽  
Evolutionary History ◽  
Gulf Of Aden ◽  
Fracture Zones ◽  
The West ◽  
Anomaly Field ◽  
The Past ◽  
History Of ◽  
International Indian Ocean Expedition ◽  
Spreading Rates

Marine geological and geophysical data from the International Indian Ocean Expedition, especially from cruise 16 of R. R. S. Discovery , have made it possible to prepare new charts of the bathymetry and the magnetic anomaly field which, together with other data, enable the evolutionary history of the Gulf of Aden to be worked out. Over the past 10 Ma the theory of seafloor spreading can account satisfactorily for the features of the Sheba Ridge and provides evidence of spreading rates in the direction of the fracture zones varying from 0.9 cm a -1 per limb in the west to 1.1 cm a -1 per limb in the east. Between the initial creation of the Gulf and 10 Ma ago, the evolution is less certain, although the geophysical evidence indicates that the crustal structure of the Gulf outside the Sheba Ridge is oceanic.

A History of the World Semiconductor Industry

IEE Review ◽  
1991 ◽  
Vol 37 (10) ◽  
pp. 355
Author(s):  
D.A. Gorham
Keyword(s):  
Semiconductor Industry ◽  
The World ◽  
History Of
Sign in / Sign up

Export Citation Format

Share Document