Geographic location
Saudi Arabia is the largest country on the Arabian Peninsula, covering 80% of its surface. It is bordered by all the countries of the peninsula: Iraq and Jordan to the north, Kuwait, Bahrain, the United Arab Emirates (UAE) and Qatar to the east, Oman and Yemen to the south. The exact size of the country is not known, as the borders with the UAE and Yemen are not fixed. The border with Jordan was established in 1965, when the two countries exchanged land. The boundaries with Iraq are older, dating back to 1922 and the administrative reorganization carried out by the British in the region. The Al Uqair convention was signed between Iraq and Ibn Saud to define a neutral zone straddling the two countries, prohibiting the construction of towns and facilities, and preserving water resources for the Bedouins. In 1981, the two countries signed an agreement definitively fixing the border between the two countries and cancelling de facto the joint management of this zone. The management of the border with Kuwait was also fixed by the Al Uqair convention, which delimited a common neutral zone of 5,790 km². In 1938, oil was discovered in the zone, to the south of Kuwait. The two countries managed its exploitation jointly. After lengthy discussions, the two countries reached an agreement to establish a border running through the middle of the zone, perpetuating the joint management of natural resources in the area. The border with Qatar, bordering the Persian Gulf, was established in 1965. The demarcation line between Saudi Arabia and Oman was fixed in 1990 after lengthy negotiations.
The Saudi government estimates the surface area of its country at 2,217,949 km², the equivalent of Greenland. Saudi Arabia's western coastline is bordered by the Red Sea and the Gulf of Aqaba. The coastline stretches some 1,800 km from the border with Jordan to that with Yemen. Its eastern coastline is bordered by the Arabian Gulf (or Persian Gulf). These vast maritime zones are dotted with 1,300 islands, the vast majority of which are located in the Red Sea. Saudi Arabia enjoys a maritime zone of 12 nautical miles (22 km) along its entire coastline.
Geology of Saudi Arabia
The geological formation of the Arabian Peninsula coincided with that of the Alps 100 million years ago. The formation of the Great Rift Valley, which runs from the Mediterranean down to Mozambique, caused the Arabian Peninsula to slide eastwards. This gradual slide continues, and scientists estimate that within 10 million years, the southeastern tip of the peninsula will be connected to the Asian continent, and the Persian Gulf will become a vast lake. A steep mountain fold has formed on the peninsula's western and southern faces. The slopes to the east of this massif gradually descend to form plateaus and a vast plain. A second, lower escarpment crosses the country from north to south, more or less in the center. These series of mountains, plateaus and plains form a variety of natural regions, despite the desert climate that prevails throughout the peninsula.
The western side of the country is crossed by the Hedjaz mountain range. It forms a steep natural barrier between the Red Sea and the interior of the peninsula. It is bordered only by rare areas of coastal plain. On its eastern flank, the slopes drop gently and are criss-crossed by wadis, dry canyons. North of Mecca, the range rarely rises above 2,100 metres. Sparse oases, the most important of which is Medina, are used for farming. To the south of the Hedjaz, in the province of Asir, the peaks rise to 2,400 meters, with the highest peak, Jabal Sawda, reaching 3,133 meters.
The eastern part of the Hedjaz and Asir mountains form a vast rocky plateau, the Najd. Elevation varies between 1,360 meters and 750 meters. The plateau is criss-crossed by small stretches of sandy desert and isolated rocky peaks. These include Jabal Shammar, northwest of Riyadh, and Jabal Tuwaiq, in the center of the plateau. Numerous oases exist in this region, which have enabled cities such as Riyadh, Unayzah and Buraydah to develop.
Northern Saudi Arabia is geologically linked to the Syrian desert. This high plateau is criss-crossed by numerous wadis running north-south. A few oases and scrubland vegetation have made this region a choice location for semi-nomadic shepherds. The Wadi as Sirhan, an ancient inland sea, was for thousands of years an essential stopover for caravans linking the center and south of the peninsula to the Mediterranean.
To the east of Riyadh, the terrain continues to slope gently towards the Persian Gulf. The As Summen plateau, 120 kilometers wide, has an elevation of between 400 meters and 240 meters. To the east of this plateau, the gradient drops sharply to form a vast coastal zone 60 kilometers wide. The soils are gravel or sand. The Arabian Gulf coast alternates between sandy areas, marshes and natural salt flats. The sea is shallow for several kilometers at a time.
The great deserts
Three great deserts isolate the Najd plateau from the rest of the country, just as the Hedjaz forms a natural barrier between the Red Sea and the interior of the Arabian Peninsula. To the north, the great Nefoud desert covers an area of 55,000 km². Its red sand dunes, up to 90 meters high, are interspersed with wide valleys. Winter rains provide grazing grasses for Bedouin herds. In the southern extension of the Nefoud, the ad-Dahna desert forms a narrow arc separating the Najd plateau from the As Summen plateau. Iron oxide gives it a red hue at sunset, especially in its northern part. To the south and east of this arc stretches the Rub' al Khali desert, one of the most hostile in the world. This vast area of 550,000 km² is uninhabited and better known as the "Empty Quarter", because there's nothing but sand as far as the eye can see.
