|
|
|
New Data about the Tectonic Structure of the Arabian Plate by Interpretation of Space images
The third Structure: (no.3-fig.2):
It is located on the western north side of the Arabian gulf inside Saudi Arabia and Kuwait lands, it is distinguished by reflective tone differ of what surround it, its radius reaches about 150km, it is crossed by Euphrates regional fault, from the east, which extends towards north and western north, its length reaches more than 1500km.
This structure is crossed with the first annular structure by a lineament of eastern north direction of length more than 800km where it reaches Kuwait lands.
2- Fault Structures:
The Arabian plate is distinguished by the existence of the Arabian rift zone on it western borders, in addition to several fault systems of western north direction, where they extend for several hundred kilometers. There are also some regional faults which take north direction, or they take the eastern north direction.
The Arabian Rift System:
The Arabian depression forms the western borders of the Arabian plate, it extends from the Red sea in the south, and then direct towards north passing through Alaqaba gulf then Wadi Araba, Dead sea, Jordan hollow, Teberia lake, and Lebanese Boukaa where it takes east north direction, then it continues in the Syrian lands towards north through Alboukea, Mosyaf and alghab depression till the south of Turkey on an extension more than1100km.
The Arabian Rift zone forms the northern part of the African –Arabian Rift which is considered as one of the largest rifts on the glob, where it extends towards north for 6500km (Belassov 1976) from Zambezi river in the west, passing through the east of Africa then to the Arabic rift in north.
Our study (Rukieh 1991, 1993, 1994, 1997, 2001) and some other studies (Trifanov 1983, 1986, Ponikarov 1966, 1969, Barazangi. M, Seper.D, Chaimov.T, Sawaf, Lirak.R, Best.T. 1993, 1997) have shown the following:
- The rift shows left lateral displacement movement,it reaches more than 105km in the area of the Dead sea, and (12-15km) in the west north of Syria, this movement conforms with the Arabian plate one towards north, after its separation from the African plate starting from Neogene till now of average 0.5-1 cm yearly. This is in addition to the vertical movement which reaches several thousands meters in Jordan valley, Teberia and Aghab.
- The rift is distinguished by its turn towards eastern north starting from the north of Tebereia passing through Lebanese lands till Syrian Alboukea depression where it conforms to the fold and the faults of Palmyrides. Group of faults branch from it and take eastern north direction where they form inclined letter V, their continuity in this direction forms the Palmyrides faults.
- The rift forms- starting from Alboukeaaa in Syria- two main faults, not one fault as it was believed before (Rukieh 1991-1994). These two faults continue towards north where they form Alghab depression, then they continue twoards north in the Turkish lands.
- The rift is distinguished by the formation of several plunges along its course as the Dead sea, Jordan hollow, Teberias lake, Alhawla depression, AlBoukeaa, Alghab, Al’Omek and others, resulting from depression the central part of the uplift and the articulation of these faults according to the pall-apart phenomena.
- The space interpretation showed (Rukieh 1991, 1998, 2001, 2004) that there are several annular structures and arch shapes along the rift course directed to the south. Some of them are crossed by the rift faults, and the most of them are located on the eastern side of the rift it has been thought that the arch shapes are formed as a result of the rift movement toward north (fig3)
- The rift is characterized by the basalt volcanic activity which accompanied its development, especially during Meocen, Beleocene and Quaternary, whether in Jordan, Syria, and Suadi Arabia, most of them are located on the eastern side of the rift.
There are some other faults parallel and near the rift as that in the east of Alaqaba gulf, in addition to two other faults parallel to the rift inside the second annular structure, they extend for more than 200km (fig. 2-3 ) in the far west south side of the Arabian Plate there are Khalifat Hamad fault of north direction on an extension of several hundred kilometers. The studies refer that this fault is related to Precambrian where mass of serpentine ultra basic or basic or acid rocks related to Precambrian also, and they are mostly cracked, broken and mylonite with the formation of melang, (Garmanov A. X 1987).
The faults system of western north direction:
It has been shown through the interpretation (especially on schemes 1/13 million, 1/10million till 1/5million) that there are fault systems take the direction of north west/ south east composed of five main zones along the Arabian plate and they are parallel to the regional fold belt in the Iranian-Iraqi lands to the eastern north of the Arabian gulf and their direction is from east to west.
1- Euphrates fault zone:
It expands from AlRobee Alkhali area in the south, on the western side of the Arabian gulf, and it continues towards western north till reaching Syria through Euphrates depression, on an extension of more than 2000km. Euphrates faults in Syria which expand for 640km from the eastern Euphrates side which form rift basin inside the continent, and it was formed through upper Cretaceous and its landmarks disappeared by the Cenozoic occurrences Ponkapov etal.1969, Barazangi 1993, Sawaf 1993, Litak 1997.
2- AlDahnaa fault zone:
it passes near the western side of the second annular structure on the outer sides of the first annular structure and it continues on an extension about 1000km.
3-The faults zone in volcanic rocks:
in Harrat Asham, Jordan, and Wadi Sarhan in Saudi Arabia and disappear under the sediment rocks in the middle. Then they appear partially in the eastern side of the Arabian Shield. They are old faults reactivate through Miocene, Paleocene and Quaternary, they contribute in the formation of big volcanic rocks in the north of the Arabian Plate, and these faults expand for more than 1000km.
4- The displacement Najd faults:
They appear clearly inside the Nubian Arabian Shield rocks which are related to Precambrian and expand for more than 1000km. Several secondary faults are accompanied to them.
|
|
|