Rub Al Khali

Rub al Khali (rb äl khä`lē) [Arab.,=empty quarter], great desert of the Arabian peninsula, c.225,000 sq mi (582,750 sq km); one of the largest sand deserts in the world. The desert occupies much of the southern interior of the peninsula, from the highlands of the Nejd (to the north) to the plateaus of Hadhramaut (to the south); it slopes from an altitude of 3,300 ft (1,006 m) in the west to near sea level in the east. Sand dunes rise to over 660 ft (200 m) in the southwest; there are salt marshes and pans in the southeast. Rub al Khali is connected to the Nafud desert in the north by the Dahna, a narrow corridor, 800 mi (1,287 km) long. The desert comprises more than 25% of Saudi Arabia. It is extremely dry and virtually uninhabited. Oil of excellent quality has been found there and is exploited. The al-Ghawar oil field is one of the world's largest.

---

Rub Al Khali 

a sandy desert on the southeastern Arabian Peninsula, in a tectonic depression between mountains extending along the western, southern, and eastern seacoasts of the peninsula. Area, approximately 650,000 sq km.

The Rub al Khali, one of the world’s largest deserts, is a plain with elevations from 100–200 m in the east to 500–1,000 m in the west. Approximately 80 percent of the territory is covered by moving sands forming barchans (up to 150–200 m high), ridges, and individual massifs. In the east there are vast salt marshes; in places there are rocky plains. The annual precipitation reaches less than 50 mm per year; frequently there is no precipitation for several years in succession. There is no permanent surface run-off, and the ground waters are deep. In the sections not covered by sands there may be gypsum and limestone crusts. Vegetation grows primarily in the low areas between sand ridges (camel thorn, saltworts). The population, consisting mostly of Arabs, is nomadic and is engaged in camel raising. There are occasional oases on the outskirts of the Rub al Khali.