Geographic location
Saudi Arabia is the largest country on the Arabian Peninsula and covers 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 British administrative reorganization of 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 cities and facilities, allowing the preservation of water resources for the Bedouin. 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 area. The management of the border with Kuwait is also fixed by the Al Uqair convention which delimits a common neutral zone of 5,790 km². In 1938, oil was discovered in the area, south of Kuwait. The two countries manage its exploitation jointly. After lengthy discussions, the two countries reached an agreement to establish a border running through the middle of the area and perpetuating the joint management of natural resources in this area. The border with Qatar, bordering the Persian Gulf, was established in 1965. The boundary line between Saudi Arabia and Oman was fixed in 1990 after long negotiations.
The Saudi government estimates the surface area of its country at 2,217,949 km², which is equivalent to Greenland. The western coast of Saudi Arabia is bordered by the Red Sea and the Gulf of Aqaba. The coastline runs for about 1,800 km from the border with Jordan to the border with Yemen. Its eastern coastline is bordered by the Persian Gulf. These vast maritime areas are dotted with 1,300 islands, the vast majority of which are located in the Red Sea. Saudi Arabia has a maritime zone of 12 nautical miles (22 km) all along its coastline.
Geology of Saudi Arabia
The geological formation of the Arabian Peninsula is concomitant 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 eastward. This gradual shift 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 western side of the peninsula and the south. The slopes located east of this massif, gradually descend to form plateaus and a vast plain. A second escarpment of lower altitude crosses the country from north to south, more or less in its center. These chains of mountains, plateaus and plains form different natural regions very varied, despite the desert climate that prevails throughout the peninsula.
The western facade is crossed by the mountainous chain of Hejaz. 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 plains. On its eastern flank, the slopes gently drop and are crossed by wadis, dry canyons. North of Mecca, the elevation of the range rarely exceeds 2,100 meters. Sparse oases, the most important of which is Medina, allow the practice of agriculture. In the south of the Hijaz, in the province of Asir, the peaks reach 2,400 meters above sea level with the highest peak, Jabal Sawda, reaching 3,133 meters.
The east of the Hijaz and Asir mountains form a vast rocky plateau, the Najd. The elevation varies between 1,360 meters and 750 meters. The plateau is crossed by small portions of sandy deserts or isolated rocky peaks. These include Jabal Shammar located northwest of Riyadh or Jabal Tuwaiq, in the center of the plateau. Numerous oases exist in this region, which have allowed cities such as Riyadh, Unayzah or Buraydah to develop.
Northern Saudi Arabia is geologically linked to the Syrian desert. This high plateau is crossed by numerous wadis oriented in a north-south axis. A few oases and scrub vegetation have made this region a choice place 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 the south of the peninsula to the Mediterranean.
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 slope drops sharply to form a vast coastal area 60 kilometers wide. The soils are made of gravel or sand. On the coast of the Persian Gulf, areas of sand, marshes and natural salt flats alternate. The sea is shallow for several kilometers sometimes.
The great deserts
Three large deserts isolate the Najd plateau from the rest of the country, just as the Hijaz forms a natural barrier between the Red Sea and the interior of the Arabian Peninsula. In the north, the great desert of Nefud covers an area of 55,000 km². Its red sand dunes can reach 90 meters high and are interspersed with wide valleys. The winter rains bring forth grazing grasses for the Bedouin herds. In the southern extension of the Nefud, the desert of ad-Dahna, forms a narrow arc that separates 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 is nothing but sand as far as the eye can see.
