Comments on the development of rifts and transform faults during continental breakup; examples from the Gulf of Aden and northern Red Sea

1984 ◽  
Vol 104 (1-2) ◽  
pp. 35-46 ◽  
Author(s):  
Duncan Tamsett
Keyword(s):  
Red Sea ◽  
Gulf Of Aden ◽  
Transform Faults ◽  
Continental Breakup ◽  
Northern Red Sea

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 - Short discussion contributions

1970 ◽  
Vol 267 (1181) ◽  
pp. 413-414 ◽  
Keyword(s):  
Red Sea ◽  
Gulf Of Suez ◽  
Gulf Of Aden ◽  
Short Discussion ◽  
The Hague ◽  
Sea Area ◽  
Northern Red Sea

H. M. E. Schürmann ( The Hague ). I would like to remark that epeirogenetic movements in the Precambrian of the Gulf of Suez and the northern Red Sea area have been proven. They are of Precambrian age as they have been observed underneath the Hammamat (youngest Precambrian) transgression. In Palaeozoic times several marine ingressions took place and similar ingressions occurred in Permian, Jurassic and Cretaceous times, indicating continued subsidence. The big clysmic taphrogeny took place in young Tertiary times.

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.

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 - Interpretation of satellite photographs of the Red Sea and Gulf of Aden

1970 ◽  
Vol 267 (1181) ◽  
pp. 23-40 ◽  
Keyword(s):  
Red Sea ◽  
Large Scale ◽  
Lateral Displacement ◽  
Shear Zones ◽  
Poor Correlation ◽  
Gulf Of Aden ◽  
Alluvial Deposits ◽  
Total Movement ◽  
Southern Arabia ◽  
Northern Red Sea

Geological structures observed in Gemini and Apollo colour photographs suggest that large-scale translational movements could have taken place in the Red Sea and Gulf of Aden. In the northern Red Sea the apparent displacement of two pairs of shear zones and three pairs of serpentinite belts is consistent with a movement of Arabia towards the NNE of some 150 km. In the southern part of the Red Sea evidence of displacement is derived from correlation of Precambrian trend-lines, particularly at points where there is an abrupt change in the regional grain; at Ras Kasr-Al Lith (latitudes 18° N and 20° N) the total movement could be 225 km. Across the Gulf of Aden observations are in general agreement with the pre-Miocene fit proposed by Laughton (1965). Study of satellite photographs provide the following additional evidence: (1) The continuity of the Hadramawt folds (southern Arabia) in the Somali Plateau; the southern Hadramawt arch appears to be extended in the northern Somali arch. (2) Pre-drift correlation of several fault zones of WNW-ESE trend across the Gulf. The NE-SW faults, on the other hand, show poor correlation across the Gulf and appear to be related to fault lineaments within the Gulf of Aden. Across the Strait of Bab El Mandeb geological and morphological similarities in the distribution of Quaternary sediments, volcanic fields, intervening alluvial deposits, fault and drainage lineaments suggest a left-lateral displacement of Arabia some 40 km to the NNE since the Plio-Pleistocene. Such a movement could have resulted in the final opening of the Bab El Mandeb Strait.

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.

Revision of the congrogadid Haliophis (Pisces: Perciformes), with the description of a new species from Indonesia, and comments on the endemic fish fauna of the northern Red Sea

1985 ◽  
Vol 63 (2) ◽  
pp. 209-217 ◽  
Author(s):  
Richard Winterbottom
Keyword(s):  
New Species ◽  
Indian Ocean ◽  
Red Sea ◽  
Fish Fauna ◽  
Western Indian Ocean ◽  
Gulf Of Aden ◽  
Form Part ◽  
Ocean Region ◽  
Northern Red Sea ◽  
A New Species

The genus Haliophis presently consists of two species, H. guttatus (Forsskål, 1755), and a new species from Bali, Indonesia. Descriptions, diagnoses, and a key are provided for these taxa. A step cline occurs in H. guttatus, which ranges from 15° S to 30° N in the western Indian Ocean and Red Sea. Populations from 27 to 30°N differ most from those in the southern Red Sea and Gulf of Aden, but less so from those south of the equator. The step occurs between 20 and 27° N, an area from which no specimens were located, and is congruent with the distributions of at least four other taxa of fishes as well as with several populational differences in other species. This indicates that these distributional patterns may form part of a generalized track, rather than being the result of ecophenotypic effects. In the Red Sea – northern Indian Ocean region, the most common distribution of endemic fishes includes both the Red Sea and the Gulf of Aden. This pattern was not apparent in populations of H. guttatus.

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.

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